@samuelgordon 

Hi,

Was your previous phone the only device you've ever connected to your router wirelessly?

In case you own another device running Android 10 or 11 that is still able to connect to your router's Wi-Fi, then open the Settings on that device and go to "Network & Internet" -> "Wi-Fi", tap on the connection with the SSID of your router, then tap on "Share" (you probably have to authenticate yourself via fingerprint or PIN) and then you can see the Wi-Fi password below the QR code.

There may be ways to reveal saved Wi-Fi password on other devices as well.

If you remember the admin password for your router's configuration interface, then you can also log into the router's configuration interface (usually via IP address 192.168.0.1 or 192.168.1.1) and get the current Wi-Fi password(s) from the "Wireless" menu.

If you own no more devices that can still connect to the router wirelessly, then you would need to connect a computer via Ethernet cable to get into the router's configuration interface.