From what I saw Cosmic has a lot of potential and looks pretty sleek too, right now I'm using KDE it's a great desktop, but now that I have a second monitor it randomly crashes on me, I think I'll switch to Cosmic when it reaches beta.
I've been running it on my Asahi linux for a bit over a week, and while it comes off feeling a bit bare bones, I've had no stability issues despite it being an alpha, in fact all issues I've had are minor, in fact the biggest issues come from Asahi Linux, not Cosmic.