iPhone 15 pro max major WiFi issues

My iPhone 15 pro Max will not stay connected to certain WiFi’s… especially the one at my house. The WiFi will disconnect every 2-4 days and then when I try to reconnect it will either not connect or it will say no internet connection detected, yet everyone else on the same WiFi it works perfectly. The only way I can make it reconnect is my rebooting my router. Now this sounds like a router issue so I went ahead and called BELL CANADA and they replaced my router with a brand new one and still the same issue. BELL CANADA tells me the issue is APPLE and apple tells me it’s bell. I have the bell home hub 3000 btw. Also this is my 3rd iPhone 15 pro max and with my other 2 I have tried on multiple other routers and it would also not connect so it wasn’t only my router. With this newer phone I have tried with 1 other router and it connected no problem, but at my house it wouldn’t connect. Any help would be appreciated.