While Jitsi is open-source, most people use the platform they provide, meet.jit.si, for immediate conference calls. They have now introduced a “Know Your Customer” policy and require at least one of the attendees to log in with a Facebook, Github (Microsoft), or Google account.
One option to avoid this is to self-host, but then you’ll be identifiable via your domain and have to maintain a server.
As a true alternative to Jitsi, there’s jami.net. It is a decentralized conference app, free open-source, and account creation is optional. It’s available for all major platforms (Mac, Windows, Linux, iOS, Android), including on F-Droid.
With paid for commercial meeting software available.
Or because they didn’t want to pay ongoing SAAS fees.
It’s literally nothing like that since Onlyfans is not an open source project that lets you host your own instance and run it however you like.
If you want anonymity run it yourself. If you want to use their servers it’s reasonable that they expect to know a modicum about how to verify you are who you say you are. There is literally no other way to prevent abuse other than identity verification of bad actors.