Both don't ship with their own Wayland compositor, but there are enough to choose from.
Xfce comes with a wayland session using labwc out of the box, but was also tested with Wayfire. The devs state you shouldn't hold your breath waiting for the native window manager xfwm to be ported into a Wayland compositor, since they don't know if/when it will be done. Almost all other Xfce components support Wayland now, while retaining X11 compatibility.
LXQt's newest stable release has full Wayland support, with 7 different Wayland compositors to choose from within a GUI settings menu: Labwc, KWin, Wayfire, Hyprland, Sway, River and Niri
https://xfce.org/about/news/?post=1734220800
https://lxqt-project.org/release/2024/11/05/release-lxqt-2-1-0/
It seems window management part is putting significant challenges, which I guess is for the exact reason - tight coupling of WM and compositor. Maybe XFCE won't get a full port?
That sounds likely, at least any time soon. It would be a lot of work to get up to par with the other implementations I'm sure.