It's well possible that some people update DNS records for their own domain every minute.

I can see 15% changing daily. There's all sorts of stuff being done with dkim and other anti-spam technologies that require a txt or cname or whatever change in DNS. Companies are always whitelisting vendors and mass mailers to send as them, validating domain ownership, adding new sub-domains, changing things for Exchange/365/Google/AI stuff, changing things due to a security audit, etc.

I imagine a renewal is a change event to, at least change the expiry, and renewals are constantly happening.

Quite possible, especially with Let's Encrypt DNS challenges.

It's probably more like most domains barely change at all but some of them change a lot.