Are dynamic DNS services no longer a thing?
All but the worst of the worst providers have an API of some sort and if you're savvy enough to set up BIND, you can handle writing a curl command to post your IP to the API and sticking it into cron.
Works in the free tier as set and forget. As long as you keep updating it (with whatever API), it works. Filling out a form manually makes NoIP sound like a horrible service.