Casio MTP-4500 not working after battery change

Hi! So I have this Casio MTP-4500.

It was my daily until I've got a smartwatch.

2 years later I want to go back

Naturally the battery died and I changed it.

But the watch didnt restart. Old bat show 0.3v and the new show 1.53v

On the net it was said to do a "reset" by touching positive and negative, didnt change anything.

Someone said on the net that the mecanism was gripped and needed to warmed (meh ok?) so I heated it with a lowpower heatgun. No change.

Is there anything more to check/do? Im surprised that a Japanese Casio just broke like that

Thanks!