There's tons of memes and stuff, but I was never into that, so meh. My thing was specialized nerd groups and they are mostly not here yet. With time, maybe they will come.
Same here. I mostly hung out in smaller, hobby subreddits. And the few I've found here are mostly dead. I really want to nerd-out with other people about shit nobody else cares about
Are you making any sort of posts in those "mostly dead" communities? There might be more people looking to join but had the same thought as you. Even a quick hello post could help a lot.
Lemmy is more picture oriented, like Instagram sort of. Reddit at least I'd you used old and shut off custom css, was more textual. -1 for Lemmy there I'm afraid.
Reddit isn't going anywhere. Chances are very likely that Lemmy's growth will just plateau and stall once all this blows over. As mentioned frequently here, Lemmy's lack of accessibility and ease of use will prevent many from joining.