I managed to fix the issue, I think it had to do with permissions, but I’m not entierly sure (some snmp config was also edited). Below are the history of the commands I used after I posted the original post:
The actual problem lies in the character sets used by the DB encoding, using nordic letters in the password of the DB user causes the webinstall to fail, see: [Solved] Installation problem - webinstall mysql access denied
250 ls -ld /opt/librenms/
251 less /opt/librenms/snmpd.conf.example
252 less /etc/snmp/snmpd.conf
253 sudo less /etc/snmp/snmpd.conf
254 sudo cp /opt/librenms/snmpd.conf.example /etc/snmp/snmpd.conf
255 less /etc/snmp/snmp.conf
256 less /etc/snmp/snmpd.conf
257 sudo vi /etc/snmp/snmpd.conf
258 sudo vi /etc/snmp/snmp.conf
259 sudo apt remove snmp
260 sudo apt install snmp
261 sudo vi /etc/snmp/snmp.conf
262 sudo rm /etc/snmp/snmp.conf
263 sudo vi /etc/snmp/snmp.conf
264 sudo apt remove snmp
265 sudo apt install snmp
266 sudo vi /etc/snmp/snmp.conf
267 sudo vi /etc/snmp/snmpd.conf
268 sudo curl -o /usr/bin/distro https://raw.githubusercontent.com/librenms/librenms-agent/master/snmp/distro
269 sudo systemctl restart snmpd
270 sudo systemctl status snmpd
271 cd /opt/librenms/
272 ./validate.php
273 sudo reboot
274 cd /opt/librenms/
275 ./validate.php
276 sudo vi /etc/snmp/snmpd.conf
277 sudo systemctl restart snmpd
278 ./validate.php
279 sudo vi /etc/snmp/snmpd.conf
280 sudo chown -R librenms:librenms /opt/librenms
281 sudo setfacl -d -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
282 sudo setfacl -R -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
283 sudo chown -R librenms:librenms /opt/librenms
284 sudo setfacl -d -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
285 sudo setfacl -R -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
286 snmpstatus -v2c -c MyROGroup 127.0.0.1 sysStatus
287 sudo vi /etc/snmp/snmpd.conf
288 git tag
289 git checkout 201602
290 sudo git checkout 201602
291 ls -ld ./
292 ls -ld /opt/librenms/
293 ls -ld /opt/librenms/logs/
294 cd /opt/librenms/
295 cd rrd
296 sudo apt install php-pear
297 sudo reboot
298 cd /opt/librenms/
299 ls -l
300 sudo vi config.php
301 ls -l
302 history