@PiKa
Where did you get the rechargeable button cell from?
taobao or shopee.
mine replaced and using for 2~3 years. so far no issue.
i follow youtube guide, it is not too complicated!
remember to apply some silicone sealent to the o-ring before closing the back lid~
also try to do it on a dry day or in a aircon dry room, it helps with reducing the moisture inside.
for watch with many moisture inside, maybe can put into dry box (with the watch backlid opened) to wick out the moisture before doing the battery replacement.