Basically what is said on title: Mouse Mark and Mouse Click animations don't activate with Wacom tablet. They work fine with mouse and touchpad.
Mouse mark isn't particularly useful, but mouse click animations are useful for presentations, lessons and video recording, for instance.
STEPS TO REPRODUCE
1. Enable Mouse Mark and Mouse Click Animation
2. Bind a keyboard shortcut for them
3. Attempt to use both effects with tablet
Mouse mark can't scribble on screen.
Mouse click animation does nothing.
Mouse mark scribbles on screen.
Mouse click animation works and show touches on screen.
Note: on Xorg both effects work perfectly, similarly to mouse and touchpad.
EffectsFilter (in input.cpp) is not taking tablet events into account. Confirming.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/1914
Git commit 354857e9f115e7335a38c1e57345f18fd2e2fa12 by Aleix Pol Gonzalez, on behalf of Aleix Pol.
Committed on 21/01/2022 at 09:33.
Pushed by apol into branch 'master'.
mouseclick: Also decorate tablet events
M +53 -1 src/effects/mouseclick/mouseclick.cpp
M +13 -0 src/effects/mouseclick/mouseclick.h