Starting from Fedora 25, the default GNOME Shell desktop environment has always used Wayland by default. The Fedora 34 KDE customized version, which will be released next spring, is also planning a similar migration, and its KDE Plasma desktop will use Wayland by default.
Wayland support for Plasma and related KDE components has been improved recently, many bugs have been fixed, and because of Wayland’s priority goals, there are other improvements. By early 2021, Fedora 34 plans to switch from the X.Org-based session used by Fedora KDE Spin by default to the modern Wayland session currently used.
With the launch of KDE Plasma 5.20, the KDE Plasma desktop environment has reached such a point that almost all common functions in the desktop and all major applications can be used in the Plasma Wayland environment of all mainstream GPUs (including NVIDIA using proprietary drivers). Starting with Plasma 5.20 in Fedora 34, the Fedora KDE team will change the default configuration of Wayland and X11 Plasma session to make Wayland the first choice and default to using, while allowing X11 session to be selected as an alternative desktop environment option.
The modification proposal of the Fedora KDE team is to change the default session of the SDDM display manager so that the Wayland-based KDE Plasma desktop is better than the X11 session. Unless there are any major issues in the coming months, this proposal will most likely be approved.