Can no longer connect to my bangle.js 2

Maybe even a hot water bottle could work. I have done one mine with a hot air gun and without setting it to 140°C I could not get it to budge. That was hot enough to let the display go blank. It recovered completely but that did not feel save.

Sadly my (previously working) Bangle 2 seems to have succumbed to the same issue - I can no longer connect to it via Bluetooth. In particular, it is no longer discoverable on any other device (tried 3 smart phones, a laptop and a desktop, all of which see my other 2 Bangles without issues; made sure it is programmable in settings, also performed a factor reset);
does not show up as Dfutarg in DFU mode, either; nor does the pinch trick mentioned above seem to have any effect. Curiously, this is the newest of 3 Bangle 2s I own (the first 2 were Kickstarters). It did not get wet (beyond wearing it regularly).
Any advise?

@user113695 thanks for trying all of that. It does sound a lot like a hardware failure then - although it's particularly strange to have one from a newer batch to have issues. How old is it?

I'll ask Christine to get in touch about a replacement

Thanks, I appreciate that. The watch was purchased last April.