If you already use Posthog, Web Analytics has been in Public Beta for quite some time.[1]
If I remember correctly, CloudFlare Analytics does not need you to register your domain with them. I personally feel keeping domain registration coupled with your DNS provider is not a good idea.
Plausible[2] has an Open Source self-hostable version but is not so updated in sync with their SaaS version.
Umami[3] is another simple, clean one. And, of course, as many have suggested, Matomo is the other well-established one. If you want to avoid maintaining a hosting routine, a lot do the hosting out of the box these days. PikaPods[4] was good when I tried and played around for a while.
1. https://posthog.com/docs/web-analytics