If you want to fill the gap on your home screen where rif was (RIP and thank you!), I have made good experiences with Connect for Lemmy: https://play.google.com/store/apps/details?id=com.kuroneko.lemmy_connect (was not too happy with Jerboa).
The content is not the same but already good enough for bored scrolling.
No idea if it’s open source. But pretty sure RiF wasn’t? I get people preferring open source an all. But at the same time, I also don’t expect everyone to make stuff for free. I paid for RiF and it was worth every penny. This is the closest app to RiF so far. Still need some improvements, but it’s much nicer than Jerboa, which is the other app I tired. And I’m not liking wefwef either.