You can set up your domain to have very short TTL (like 2 minutes) and have a script polling your external IP every 2 minutes to watch for IP changes, then have

You can set up your domain to have very short TTL (like 2 minutes) and have a script polling your external IP every 2 minutes to watch for IP changes, then have the script change the records of your domain when the IP does change. Most nameservers provide a REST API for updating records so this is very easily done.