Any DNS provider is good if they offer an API that lets you use PUT to modify DNS records. You can make a small bash script and crontab it. I also used DuckDNS for a while, and it worked fine.

It has the Firefox extension “Wallabagger”, open-source and all. You just have to create a token in Wallabag, link it, and then it works like a charm. Doesn’t work exactly like OP wants though.