This isn’t my experience at all. Mastodon feels more or less exactly like Twitter-circa 2022 to me (just with fewer right-wing trolls) - still fun and vibrant and also informative.
Lemmy feels like a collection of weird freaks trying desperately to be cool. And don’t get me wrong, I’m one of them. But I would not call the vibe here “vibrant, active, lighthearted, fun” or certainly “powerful.”