A lot of providers have basic DNS for free but charge for more sophisticated uses like geo routing. AWS charges for every single thing: https://aws.amazon.com/route53/pricing/

I refuse to use Cloudflare for two reasons:

1) It’s free until it’s not and they don’t tell you where that limit is.

2) If something goes wrong you cannot contact anyone unless you have an enterprise agreement. Just paying them money is not enough to be able to speak to a person. I had serious issues with R2 and had no-one to contact. They have a Discord and you see people posting the same issues over and over again that never get fixed.