Stop adding an entry to known_hosts for Dynamic IPs
Warning: Permanently added the ED25519 host key for IP address '[198.51.100.1]:1234' to the list of known hosts. Is what I see when I connect to my parents house as they have a dynamic IP.
Put CheckHostIP no in your ~/.ssh/config file.
eg.
Host *
CheckHostIP no
or
Host dynamic.example.com
CheckHostIP no
It took me a bit of searching here is my source.