That's very much down to the developers of the watch faces @Kevin1007
I agree that would be nice.
Some developers put little mini videos in their pages and some YouTube reviewers have the faces and show them working when reviewing them.
I personally look at YouTube to see if the watch face I'm interested in is ok.
Some YouTube reviewers concentrate only on Samsung watch faces.
Current Phone ~
Samsung Note 20 Ultra 5G SM-9820 _256Gb SnapDragon 865+
Samsung One Ui 2.5/ Android 10.