If you update to Ubuntu LTS (version 22.04), you will want this in your
PubkeyAcceptedKeyTypes +ssh-rsa HostKeyAlgorithms +ssh-rsa
Failure to do that gets you this:
Unable to negotiate with best-friend.server.ssh port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss
The dear old NSA of the USA is gently shoving everyone away from effective cryptography towards backdoored nonsense, so you need to now tell your ssh that you want to be able to connect to older servers with fewer cryptographic backdoors.