It's tricky to try out since it's invitation-only. As far as I understand they want to focus more on long-form content and high-effort posting, so it's not really a Reddit alternative per se.
As for Lemmy is Fun, it doesn't look particularly likely, though talklittle (the dev) at least made a Lemmy account , so your prospects are at least better than fans of Baconreader. Maybe the future chances are at least non-zero, provided Lemmy continues to grow.
I'm currently testing out connect and it seems a lot like infinity. Swipe to go from post to post and a lot of other customization. I didn't like liftoff because of it but that might change. If boost can do this I might try it.
I really, really like connect. But I'm in a sub for a word game, and the only way to spoiler the screenshots (so that I can read the clues, but not get the answer) is to NSFW tag it. Connect still shows the unblurred images, even if I choose to have blur turned on. I'm on Jerboa until that gets fixed. Since you use connect, have you found a problem like that with yours?