Last few days watch has stalled on charge at 75% with a message waiting saying it cannot continue until the battery has cooled. Google shows up similar issues from December last year. What the hell is going on, watch is just over a year old.
Assuming your using the original charging wire and dock i'd suggest to reset the watch.
If that fails try using another another official dock and cable.
The watch is covered by a 24 month manufacturing warranty so a Samsung Experience Store or Samsung Service Centre location can run a diagnostic on the watch.
I wish you all the best with this situation.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.