Macbook doesn't show battery icon, charger shows green light and computer will turn off if unplugged, even though I kept it plugged all night

I left it plugged for a couple of days and now I can't see the battery icon. Also, If I unplug it, it turns off and doesn't turn on unless is plugged again, the light never changes to amber so I guess is not charging at all.

I changed the battery 3 months ago, in a Mac authorized shop, I also added a solid hard disc and replaced the DVD player it had. I don't want to reinstall the OS because it's an old computer and it won't work as well with the new OS. Any ideas?

Mac OS Catalina 10.15.7

MacBook Pro (15-inch, Mid 2012)

Processor 2.3 GHz Quad-Core Intel Core i7

Memory 16 GB 1600 MHz DDR3

Start up disk Mac SSD

Graphics Intel HD Graphics 4000 1536 MB