I use Mythic Beasts as my domain registrar, they have a DDNS API endpoint. Nice design, you can basically just ping it with your public key to update the DDNS entry to your origin IP (or manually set it in the request, if you want to introduce another point of failure).

I have a cron job that runs every 15 minutes that hits that endpoint, literally just a one-liner script. I have never understood why everyone is using entire libraries for such a simple operations.