battery % is not increasing #struck

I'm having a similar problem.

My Surface Studio 2 stops at 50% and won't charge after that.

If you'd like to try, there's a flag in the UEFI BIOS that disables intelligent battery charging.
To access the BIOS, you have to turn on the Surface while holding down the volume up button until the BIOS starts.
By disabling intelligent charging in the boot menu, the battery charges up to 100%.
However, if you use your PC for a long time while connected to the mains, this will damage the battery (over time).

Changing this option is very inconvenient (you have to restart the PC every time) and the "surface" app, you can download from the store, allows you to use a button that temporarily enables 100% charging, but it only worked once for me; now the button is always disabled :-(

W11 is supposed to indicate "smart" charging with a little heart on the battery icon, but it hasn't appeared on me for a while. It either charges to 50% or, with the BIOS option, goes to 100%.

Theoretically, smart charging should stop at 80%.

Does anyone have more information?

Does it happen when you have used the Windows 10?
Is your device come with battery charging LED?
Try shutdown your PC and take off your battery and power on your PC without battery.

Then use your PC for a while and shutdown it and connect your battery and let it charge without turn on your PC and then turn it on and check your battery status.

What is the manufacturer of your PC?