Fedora desktop (any DE, and most desktop distros, for that matter) uses networkmanager to configure networks, because it is powerful and offers an API for DEs to configure networks, so as long as you have the drivers, networking will work the same. However, If I recall correctly, Gnome and KDE use the same frontend library for networkmanager, just with different GUIs, so they really are going to be the same, and they have for many years. Cosmic being new and rust based might have rolled its own frontend or used a different library, and it might not be as mature as what the other DEs use.
Try configuring your WiFi manually, editing networkmanager’s config files directly, instead of the gui. And see if that work.
I would even suggest straight up copying the config files produced by gnome or KDE.
Fedora desktop (any DE, and most desktop distros, for that matter) uses networkmanager to configure networks, because it is powerful and offers an API for DEs to configure networks, so as long as you have the drivers, networking will work the same. However, If I recall correctly, Gnome and KDE use the same frontend library for networkmanager, just with different GUIs, so they really are going to be the same, and they have for many years. Cosmic being new and rust based might have rolled its own frontend or used a different library, and it might not be as mature as what the other DEs use.
Try configuring your WiFi manually, editing networkmanager’s config files directly, instead of the gui. And see if that work. I would even suggest straight up copying the config files produced by gnome or KDE.