I think the instances that cater to a niche have been largely spared the fediverse breakdown. ttrpg.network seems to be chugging along fine. Probably wasn't a good idea to attempt to recreate reddit on a single instance. Would've been smarter to have lots of smaller instances catering to broad topics of interest.
I signed up through Lemmy world and there's been lots of issues with some of the apps...(I also signed up through Aussie zone too cos I was confused, but have mainly used the Lemmy world one to comment). I think you're right and it probs has alot to do with the large influx of users...
(& I also have 'pending subscriptions...)