Hello.
Battery replacement by the user is not supported, and doing so may damage the device. After some research, I found several procedures published on the Internet, but they seem to be difficult.
I strongly recommend that you get your Surface serviced or repaired, or ask a local computer repair specialist.
[Surface Service and Repair]
https://learn.microsoft.com/en-us/surface/surface-service-options
[How to get Surface service or repair]
Thank you in advance.