I see a lot of people using https://luma.com/. I'm sure it's not as big as Meetup but it does have a decent community of users, and you can set up pretty much anything with their free plan.
I've looked at Luma and have mixed thoughts. The UI is a massive improvement over Meetup. However, it seems to be following the standard VC funded business model of attracting users and pushing excessive monetization once users are dependent.
It's about the user bases - Luma and Partiful are almost entirely professionals in careers like Tech, Finance, or Entertainment (especially LA), and the events almost always vet before accepting people.
This helps ensure a better noise to signal ratio that Meetup simply couldn't provide.
Interesting point, but I personally didn't find Meetup had a noise issue. You could filter for the right stuff, pretty easily. Also I don't see how Luma/Partiful will avoid this problem eventually.