Thank you, I've just done and I've noticed I've been quite messy in my request.
I'll try to be as precise as I can.
- I have a FTTC connection, at the moment my max speed is about 110mps.
- There are about 50 clients connected while I'm writing (lots of IoT sensors and stuff), almost all via wifi, but just my 4 or 5 of them could use bandwith (smartphones, TV Sticks, notebooks...). The number is increasing in the future.
- No needs for USB ports, I have a media server, a smarthome server and NAS server.
- VPN had been useful while on holyday to check and fix some issues I had had, but it's not an all-day need.
I've ended up here https://forum.openwrt.org/t/best-2021-openwrt-wifi/84674/42 but where I live I can't find any of the mt7622b routers and R7800 seems abandoned.
I think I'll have a look at the ZyXEL nbg6817, quite expensive but it could be worth it to have a stable network.