Question about Gigabyte B650 EAGLE AX

In the OS yes. In Ubuntu Linux just turn them off in the configuration panel. Also certainly possible via the BIOS. But why? Just buy a cheaper board without BT or WLAN.

You can - but why not just buy the same board without the WLAN AX module?

Yes you can. Either in bios or windows/linux

You should deactivate the network adapter for wireless connections in the system settings. However, if you have a LAN cable plugged in, the connection is made via the cable anyway