It depends on what you would consider stable. I would install it alongside gnome for now and try it out. You can just leave it on your system getting updates while you use gnome and just pop in every once and a while. It’s up to you if you want to enable cosmic-greeter and disable gem for your login page, but if you want stability, just stick with gdm for now.
I use Yazi and its amazing. Here’s their docs on how to set it up as a file picker in helix.
https://yazi-rs.github.io/docs/tips/#helix-with-zellij