I'm familiar with the BAKOM website which shows cell towers on a map. However, I couldn't find details of which mobile provider was present at a cell tower location.

Does anyone know where I can get this information? I'm trying to figure out detailed coverage by provider in my location.

I guess you should try on the provider website.

https://scmplc.begasoft.ch/plcapp/pa...sf?netztyp=lte
https://fiber.salt.ch/it/mobile/coverage

Even if you had that information was there no way you could possibly figure out detailed coverage.. it depends on WHAT a provider has exactly installed at each tower, how much traffic he is forecasting in a region and dozens of other factors, say the height of a tower. There are very complex software tools used to estimate the networks for planning and even those get it pretty wrong at times...

well you could figure out if there are no 5g/4g towers for a particular provider and rule them out.

Everybody other than the three licensed mobile providers will say to not rely on their data, including the cantonal Amt für Umwelt BAKOM says to contact.

With the complement of the sunrise coverage:
https://www.sunrise.ch/de/privatkund...ungskarte.html
you have the three main mobile provider.

actually every phone has hidden settings that show all the network related parameters and you can see signal strength , attenuation , signaling , BTS,BSC you connecting to , next few towards signal (so triangulation is possible ) etc etc

I think the best would be to travel the regions with your 4G/5G activated and extrapolate the results. You have got quite a swathe of land to be covered. Repeat it several times for better accuracy and data truncation error. Take your time. That should be a PhD project for ETH candidate student.