Im joining in on the reddit ditching thing, and was kinda worried at first that i wouldnt be able to like use it the way i did reddit as it feels like a whole new place, but after engaging with posts and people and actually being a part of lemmy rather than being lurk mode all the time i was pleasantly surprised with how easy it is to become a member of the community, theres a reasonable amount of subs (or whatever the other word for em is) that fit my interests, enough linux content and shitposting for my liking, and the overall random posts made by people equally fed up with Leddit. (also i admit i used reddit a little cus there was this post on the fedora sub showing how to fix a sound issue i been having after a recent update)
theres a reasonable amount of subs (or whatever the other word for em is)
I believe here its simply called "communities".
I made a account 5 days ago and have a good time so far. Like you, I was mostly a lurker on Reddit but here I started posting memes and opened discussions. I'm actually positive about the growth and longevity of the platform. There's enough content to keep people interested. I think Lemmy will be healthy stable around 10k active users. Should be possible.