ISP router wifi range

Hello Lemmy,

We finaly moved to a new place with fiber connection woop! ISP installed ZXHN F670L FTTH next to entrance door where electronic cabinet is. Appartment is just 60 m2 and we have issues with wifi signal.

Tv (Xiaomi TV stick) is mounted on the wall just 4-5 m from the router (no door, just corner of the wall is barrier from the line of sight). I can see 2.4 GHz wifi at 50% signal and 5 GHz takes like 30 sec to even show on TV menu. 5 GHz wifi is at 20-30% only and when I connect its unusable.

PC in next room is losing connection all the time and thats behind 2 walls.

If Im not just next to a router, I have better signal from 2 neighbours that use same ISP (I can tell from SSID).

I called them and they said techician will come on monday to check and possibly replace router with some Huawei model.

I still have old (coax cable) router from old place, I placed it in same spot for testing and signal is much better. Still not perfect, but TV has 80-90% and PC in next room is almost the same.

Do I just have crappy router or my walls are wifi unfriendly what do you think? I dont need super high speed on wifi, but I need stable connection (2 android phones, 1 work laptop, 2 smart switches and few smart appliances). More important devices like server and main PC are using cable connection. This router has 1GB LAN ports and Im fine with that since my speed is 300/100 only. 100 Mbps would be plenty for Wifi.

Should I stick with 2.4 GHz and fight with neighbour routers? Can I expect better signal from Huawei (sorry dont know exact model yet)? What if ISP cant provide proper solution, what wifi AP would you recommend? I could place AP in another room and connect to a router via UTP cable.

Thx in advance