I also had an idea for a wifi network where a router talks to other routers in range to setup networks independent of the internet. The idea being that, if widely enough adopted, you could potentially cut out ISPs except in situations where the signal needs to travel long distances (like rural areas). The router would have an antenna for long-range communication, and then a second antenna to actually talk to devices in a smaller range. Kinda like meshtastic, but significantly faster (with the trade-off being distance and penetration).

There are open source projects in the works for just such a thing, I forget the details at the moment but I heard about them from the Meshtastic Discord funny enough.

Look up the IEEE 802.11ah standard (or Wi-Fi HaLow) for example, it's a standard that can achieve pretty good WiFi data rates for quite a distance (enough that a neighborhood mesh would work well), whilst running on low power, sub-GHz hardware (like the Meshtastic hardware).

https://www.quectel.com/blog/what-is-wi-fi-halow-iot/

There are mesh internet projects using this, I just don't remember their names right now haha.

Sadly while it uses more or less the same frequency band as LoRa in the USA (around 900MHz), I'm not sure how useable it is here in Europe given the band licensing restrictions. I'd like to think they've thought of that! But I dunno? I've seen HaLow hardware that only used the US band, but maybe other companies price EU equivalent hardware.