It would be more reliable to use a ‘clean’ not blacklisted static IP.
But in theory you could just use ddns and update the IP. But I actually never tried it.
Mailcow comes ready out of the box. Just change the DNS entries according to Mailcow and you are good to go.
Yes thats why i said in theory. I doubt that many residential IPs are blacklisted, but still not optimal.
IPv6 only works but there are probably many Mail Servers that are IPv4 only, so you will not receive mails from them.
If you are serious about it, rent a VPS or get a static IP on your residential connection.