I built the exact same thing 5 years ago and I'm using it daily since then. I never have any problems with it. You don't need a config file for it, just a couple of CLI options and you are good to go. You can install it with pip, docker or downloading a binary:
I guess this is something people have to make? I wrote one 6 years ago in Golang and rewrote it in Rust last year. I have stopped using it, but I had them running for 6 years without issues.
https://github.com/kissgyorgy/cloudflare-dyndns