I use KDE. Some use GNOME. Most other options are probably to be left out as X11 is unsafe.
Cosmic is not nearly finished, but will probably be a bit safer, as its in rust, even though not tested.
Then there are window managers like Sway, Hyprland, waymonad, wayfire, etc.
RaspberryPi also has their own Wayland Desktop.
Is every Wayland Desktop / WM equally safe, what are other variables here like language, features, control over permissions, etc?
Could you provide some criteria for what you’re looking for in the way of security? Wayland is far better for security than Xorg, but it’s hard to say how much it varies between wayland compositors. I can’t imagine it would matter too much, but depending on how much security you’re looking for, choosing more minimal software is probably better. Rust can be better for security but I’m not entirely sure how much can really get compromised through poor memory management in a window manager.