Take a look at AREDN, the Amateur Radio Emergency Digital Network -- https://www.arednmesh.org. They use commercial WiFi gear (see https://www.arednmesh.org/content/supported-platform-matrix) with custom firmware, running on the adjacent ham radio bands (which have less noise on them, allowing for greater distance, although I wouldn't be surprised if the WiFi bands and radio bands have different allocations in Europe.) Surprisingly (to me, anyway) they say that 'N' speed WiFi works better at long ranges than newer protocols.

Honestly, as you are in Europe, you should look into the European Hamnet. See https://hamnet.eu/site/community.html and https://www.tapr.org/pdf/DCC2014-TheEuropeanHAMNET-DG8NGN.pd.... They aren't using WiFi, but the goal is the same.

Both of these require licensed amateur radio operators to use normally. (Maybe wartime is a different matter). I do believe I heard that Russia took radio transceivers away from operators in the Ukraine, but don't know much about it.