Help - Bangle.js 2: Not starting/charging after discharge

Heyhey folks, I'm having the following issue:

The watch powered off after being completely out of battery over Christmas and after multiple charging attempts, it doesn't start anymore. The watch is only 5 months old and worked fine so far, so this is weird. The screen is completely black and nothing happens when holding the power button.

What I've tried so far:

• charge overnight, then hold the power button for 2s, 10s, 30s
  
• made sure that the power adapter is facing the right direction (right when looking at the watchface, left when contacts are facing up), then charge overnight again, repeat
  
• cleaned the contacts, and charge overnight again
  
• took off the lil sticker on the back and properly wiped the contacts with alcohol wipes, charged overnight again
  
• made sure there's 5v on the charger with multimeter - charger works fine, cleaned the charger pogo pins, charged overnight... yadda yadda, nothing worked, watch ded.
  
• watch reads 0.0V on the outer 2 pins
  EDIT:
  
• tried the watch jumpstart thing with a 3V battery on pin3 and GND
  
  

Context:

• Bought 2nd August 2022
  
• Worked fine until storage corruption (resolved, thread: https://forum.espruino.com/conversations/380541/#comment16725446)
  
• Never been in extreme temperatures, so battery shouldn't be damaged from temperature.
  
  

Any help appreciated,
Thanks,
Flo