Can't mask an animation nor multimedia on digital clock

Same as topic name. I was experimenting with masks, since i wanted to make animated clock BG, but it never export and look on the watch exactly like in preview mode in WFS. Pic 1 shows the preview in WatchFaceStudio:

Pic 2 shows the screenshot from the watch itself, after pressing “Run on device”:

Is there any way to make it look like in the preview mode or should i scrap this idea and try something else?

I have no experience with masks, but can’t you solve this by hiding the image behind the mask with ‘backward’, i.e. put that image backward (see the top bar in WSF)?

It works well in my test.

on watch: