In the past, I remember being able to view the RSSI values for an LTE under Device->Wireless, alongside the RSRP, SINR, RSRQ values.
Current sub-tabs under Wireless,
The Vendor values are,
.1.3.6.1.4.1.14988.1.1.16.1.1.2.{{ $index }} = INTEGER: -65 (RSSI, MIKROTIK-MIB::mtxrLTEModemSignalRSSI)
.1.3.6.1.4.1.14988.1.1.16.1.1.3.{{ $index }} = INTEGER: -15 (RSRQ, MIKROTIK-MIB::mtxrLTEModemSignalRSRQ)
.1.3.6.1.4.1.14988.1.1.16.1.1.4.{{ $index }} = INTEGER: -101 (RSRP, MIKROTIK-MIB::mtxrLTEModemSignalRSRP)
.1.3.6.1.4.1.14988.1.1.16.1.1.7.{{ $index }} = INTEGER: 1 (SINR, MIKROTIK-MIB::mtxrLTEModemSignalSINR)
I have tried fiddling with adding a modules->sensors->dBm entry to includes/definitions/discovery/routeros.yaml with no archivable success AOW. 
Output of ./validate.php
# sudo --user=librenms /opt/librenms/validate.php
===========================================
Component | Version
--------- | -------
LibreNMS | 23.10.0-63-gdc8189b6f (2024-06-10T18:27:06+00:00)
DB Schema | 2023_11_04_125846_packages_increase_name_column_length (273)
PHP | 8.3.8
Python | 3.11.2
Database | MariaDB 10.11.6-MariaDB-0+deb12u1
RRDTool | 1.7.2
SNMP | 5.9.3
===========================================
[OK] Composer Version: 2.7.6
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database Schema is current
[OK] SQL Server meets minimum requirements
[OK] lower_case_table_names is enabled
[OK] MySQL engine is optimal
[OK] Database and column collations are correct
[OK] Database schema correct
[OK] MySQl and PHP time match
[OK] Active pollers found
[OK] Dispatcher Service not detected
[OK] Locks are functional
[OK] Python poller wrapper is polling
[OK] Redis is unavailable
[OK] rrd_dir is writable
[OK] rrdtool version ok
[WARN] Your local git branch is not master, this will prevent automatic updates. ⟵ Caused by local forking of the master branch to code PR #16103
# git -C /opt/librenms log -n 2 --oneline
dc8189b6f (HEAD -> routeros-version) RouterOS: Change the version template
63eeeb717 (upstream/master, upstream/HEAD, master) Mail Transport use BCC option (#15554)
What was the last working version of LibreNMS?
63eeeb717
Device info
RouterOS RBLHGGR
Wireless Module poller information
#### Load disco module wireless ####
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"ap-count"] 0.37ms]
clients: SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUsetX' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrWlApTable']
mtxrWlApTable = No Such Object available on this agent at this OID
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"clients"] 0.76ms]
quality: SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUsetX' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrWl60GTable']
mtxrWl60GTable = No Such Object available on this agent at this OID
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"quality"] 0.67ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"capacity"] 0.34ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"utilization"] 0.42ms]
rate: SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUsetX' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrWlStatTable']
mtxrWlStatTable = No Such Object available on this agent at this OID
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"rate"] 0.63ms]
ccq: SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"ccq"] 0.4ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"snr"] 0.36ms]
sinr: SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUsetX' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrLTEModemTable']
mtxrLTEModemSignalRSSI[3] = -67
mtxrLTEModemSignalRSRQ[3] = 0
mtxrLTEModemSignalRSRP[3] = -132
mtxrLTEModemCellId[3] = ******
mtxrLTEModemAccessTechnology[3] = 7
mtxrLTEModemSignalSINR[3] = 1
mtxrLTEModemEnbId[3] = *****
mtxrLTEModemSectorId[3] = 90
mtxrLTEModemLac[3] = ****
mtxrLTEModemIMEI[3] = ***************
mtxrLTEModemIMSI[3] = ***************
mtxrLTEModemUICC[3] = ********************
mtxrLTEModemRAT[3] = LTE
SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUs' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrInterfaceStatsName']
mtxrInterfaceStatsName.1 = lo
mtxrInterfaceStatsName.2 = ether1
mtxrInterfaceStatsName.3 = lte1
mtxrInterfaceStatsName.4 = lte
mtxrInterfaceStatsName.5 = lobridge
mtxrInterfaceStatsName.6 = ltebridge
Discovered LibreNMS\Device\WirelessSensor Array
(
[sensor_class] => sinr
[device_id] => 21
[sensor_oids] => [".1.3.6.1.4.1.14988.1.1.16.1.1.7.3"]
[sensor_index] => 3
[sensor_type] => routeros
[sensor_descr] => lte1: Signal SINR
[sensor_divisor] => 1
[sensor_multiplier] => 1
[sensor_aggregator] => sum
[sensor_limit] =>
[sensor_limit_warn] =>
[sensor_limit_low] =>
[sensor_limit_low_warn] =>
[sensor_current] => 1
[entPhysicalIndex] =>
[entPhysicalIndex_measured] =>
[rrd_type] => GAUGE
[access_point_id] =>
)
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_type`=? AND `sensor_index`=? [21,"sinr","routeros",3] 0.68ms]
.SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_id` NOT IN (?) [21,"sinr",141] 0.3ms]
rsrp: Discovered LibreNMS\Device\WirelessSensor Array
(
[sensor_class] => rsrp
[device_id] => 21
[sensor_oids] => [".1.3.6.1.4.1.14988.1.1.16.1.1.4.3"]
[sensor_index] => 3
[sensor_type] => routeros
[sensor_descr] => lte1: Signal RSRP
[sensor_divisor] => 1
[sensor_multiplier] => 1
[sensor_aggregator] => sum
[sensor_limit] =>
[sensor_limit_warn] =>
[sensor_limit_low] =>
[sensor_limit_low_warn] =>
[sensor_current] => -132
[entPhysicalIndex] =>
[entPhysicalIndex_measured] =>
[rrd_type] => GAUGE
[access_point_id] =>
)
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_type`=? AND `sensor_index`=? [21,"rsrp","routeros",3] 0.29ms]
.SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_id` NOT IN (?) [21,"rsrp",142] 0.26ms]
rsrq: Discovered LibreNMS\Device\WirelessSensor Array
(
[sensor_class] => rsrq
[device_id] => 21
[sensor_oids] => [".1.3.6.1.4.1.14988.1.1.16.1.1.3.3"]
[sensor_index] => 3
[sensor_type] => routeros
[sensor_descr] => lte1: Signal RSRQ
[sensor_divisor] => 1
[sensor_multiplier] => 1
[sensor_aggregator] => sum
[sensor_limit] =>
[sensor_limit_warn] =>
[sensor_limit_low] =>
[sensor_limit_low_warn] =>
[sensor_current] => 0
[entPhysicalIndex] =>
[entPhysicalIndex_measured] =>
[rrd_type] => GAUGE
[access_point_id] =>
)
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_type`=? AND `sensor_index`=? [21,"rsrq","routeros",3] 0.31ms]
.SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? AND `sensor_id` NOT IN (?) [21,"rsrq",143] 0.28ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"ssr"] 0.25ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"mse"] 0.26ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"xpi"] 0.25ms]
rssi: SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"rssi"] 0.28ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"power"] 0.3ms]
noise-floor: SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"noise-floor"] 0.28ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"errors"] 0.25ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"error-ratio"] 0.28ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"error-rate"] 0.26ms]
frequency: SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"frequency"] 0.31ms]
distance: SNMP['/usr/bin/snmpbulkwalk' '-v3' '-l' 'authPriv' '-n' "" '-a' 'SHA' '-A' 'PASSWORD' '-u' 'USER' '-x' 'AES' '-X' 'PASSWORD' '-OQUsetX' '-M' '/opt/librenms/mibs:/opt/librenms/mibs/mikrotik' 'udp:HOSTNAME:161' 'MIKROTIK-MIB::mtxrWl60GStaTable']
mtxrWl60GStaTable = No Such Object available on this agent at this OID
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"distance"] 0.56ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"cell"] 0.33ms]
SQL[SELECT * FROM `wireless_sensors` WHERE `device_id`=? AND `sensor_class`=? [21,"channel"] 0.33ms]
>> Runtime for discovery module 'wireless': 0.3040 seconds with 200896 bytes
>> SNMP: [1/0.04s] MySQL: [27/0.10s] RRD: [0/0.00s]
#### Unload disco module wireless ####