I have the same issue - although I’m also “lucky” to live somewhere that a lot of people emigrated from and took placenames with them to Canada, USA, Australia, New Zealand, South Africa… so my devices by default get dumped in those. With Observium, it was possible to use DNS_LOC records to set the devices exactly where I wanted them (in my case so I could arrange a 3 floor building with the floors side-by-side to be able to see them spatially sensibly) - with LibreNMS that’s no longer possible.
You can add the Latitude & Longitude in square brackets - so [51.0000.-3.0000] - if the device allows it and the SNMP Location string isn’t too long (yep, I have devices that don’t allow or . in SNMP locations)