An old forum I used to frequent had a downvote system that required you to specify a reason for why you felt that post or comment required a downvote. That reason (and the account that submitted it) was visible to the person whose post got downvoted and to the moderators, but to no one else.
It still worked well for filtering out troll posts and spam, and legit posts were almost never downvoted as you couldn't do so fully anonymously and moderators could take action when you abused the system.
I could see this becoming highly impractical when communities become as huge as on Reddit though, but for a smaller forum that one had a few hundred active users it worked really well.
I'd say just try it and see what you prefer. The app also has some occasional weirdness as it's still an alpha version, but it usually works well.
I just prefer having it in an app, and the app is tiny anyway (about 20MB on my phone).
I still mostly enjoyed it, but I do agree that it's way overhyped. The game has a ton of great and fun moments, but it also has so much filler that causes the sense of progression to really grind to a halt.
It's a game that IMO would have benefited from leaving some parts on the cutting room floor, but otherwise it's not a bad game.
I'm trying to switch from Rif to Jerboa too. Setting up an account and the front page was a bit unintuitive, but once that was done the app works very well and feels at least somewhat similar to Rif.
I'm glad some people have been posting guides though, those really helped as the fediverse is still rather new to me.
I've had similar issues signing up from the Jerboa app too. It seems that in some browsers it can't show a notification when a username is not valid, and when it fails to show that notification then the loading animation just plays indefinitely.
Switching to a browser made it show the notification, and when changing the username to one that's valid it did work from the app too.