Note that 802.11r is only useful if you’re using WPA enterprise authentication (certificates and radius and all). Most home networks use WPA personal pre shared keys (aka here’s my Wi-Fi password).
802.11r accelerates the multi step handshake that you have to perform with WPA enterprise when you roam from one access point to another. There is a much shorter handshake for WPA personal so there is no advantage to enabling 802.11r if you’re not using Enterprise auth.
Not entirely true: for WPA2 it is the case that all APs and clients use the same key, but even in that case, 11r adds mobility domain and FT-PSK and results in more devices having better roaming.
For WPA3-SAE and WPA3-OWE it is required as each client has a different (session) key.
Agreed it's best to connect the access points with Ethernet.