Check out Alexandrite! It’s an alternative Lemmy UI.
It supports many different instances (must be 0.18.1+, I believe) including lemmy.world and lemm.ee. I think it looks really good, it’s really smooth, and even has some nice features like live Markdown preview.
Yes it’s primarily a desktop UI. I personally love it on my widescreen and use it as my default frontend for lemmy.