Looking for help setting up an alternative to DuckDNS

Hi all.

I've got an old server PC that I use as a home server. Since my IP address sometimes changes due to my internet provider, I've been using DuckDNS and this DuckDNS crontab to keep the IP address up to date. But I've been having issues with DuckDNS not working reliably lately, and I thought that since I have a couple of domain names that I'm not using, I might try using one of those instead.

Problem is, I don't know where to start, either to get the domain pointing to my IP address, or to keep it updated when my provider changes my IP address.

Does anyone know of a guide that can walk me through this?