If I'm not mistaken, drm-kmod will no longer be a separate repository in FreeBSD "15-RELEASE". So, Wayland support is moving towards parity with X11and both should be equally viable. Architecturally, Wayland appears to have more potential than X11 across simplicity, security (e.g. app isolation), and efficiency, even if the various desktop implementations are still maturing.
As far as the "default", I think that depends more on one's chosen desktop environment than BSD. Some DEs, e.g. Sway (one of my favorites),
only work with Wayland. Other DEs like KDE (and GNOME) are moving towards Wayland and away from X11, and those are the two major desktops. So there's your bellwether for "default". Wayland is absolutely the default for KDE and GNOME now, and as mentioned, some other DEs support Wayland
only, so the concept of default for these doesn't even apply - it's not the default, it's the
only.

FreeBSD is not necessarily pushing Wayland, per se. Rather when the window system itself transitions to a particular technology and two major desktops favor support of it, one must go with the flow at that point. (GNOME binding to systemd a separate topic). So FreeBSD is simply embracing Wayland as an intelligent acceptance of reality.
May Find Interesting ( as I did

)
...
Another aspect that I have come to understand is that X11 and Wayland are not enemies. From all the X11Libre drama, one might think that they are.
X11 - Wayland is "X12"
Display server expert Daniel Stone explains what is really happening with the future of graphical display protocols on Linux.
www.linux-magazine.com
Many X11 Engineers now work on Wayland:
gitlab.freedesktop.org: wayland/wayland.git
gitlab.com
Matt Turner - X11, Wayland
Olivier Fourdan - XFCE Author
Simon Ser - Sway
...
...
So, ultimately, Wayland is an engineering decision by X11 and Wayland is the next "major version" of X11, as opposed to a competitor to X11. Also FreeBSD support is included in the Wayland repository, which is a great statement about the future of FreeBSD for desktop usage!
Just search for FreeBSD!
gitlab.freedesktop.org: wayland/wayland.git
gitlab.com