I've been seeing Lu.ma quickly rise in popularity as the "RSVP platform-of-choice" over the incumbent Meetup for a number of tech meetups across Scotland.
I'm sure cost is a factor, but I also wonder if there's greater ease-of-use or simpler data management which is causing this migration. Reminds of a similar parallel I've observed with dev-teams migrating from JIRA to Linear.
As for the code jam, it looks to be a big 'un -- looking forward to seeing many familiar faces there!