Start by typing 'Powershell' into your Start search box, bottom left. It'll be the top match and, in a tweak to WC's instructions, the trick is to click/tap on 'Run as administrator' - if you run PowerShell as a regular user then you'll get a permissions error on the tool.
Once PowerShell is up and running, type (and the destination file/location is up to you) 'powercfg /batteryreport /output "C:\batteryreport.html' and press Enter:
Now dive into your favourite file manager (e.g. File Explorer, built into Windows) and find your output file and double click/tap it, to open it in your PC's default web browser:
Above, down the bottom, you can see the estimated 'full charge capacity', which will be slightly less than the 'design capacity'. And by how much is how far your battery has deteriorated since new. In my case with the Surface Go here, I'm only down just over 1Wh in over two years of use, which is splendid.
Browsing further down the battery report listing, there's lots more detail:
And you can even track your battery's charge capacity over time, though I agree that we're in stupidly crazy levels of detail now!
All worth noting, in terms of a free and relatively easy way to check on your mobile PC's battery health. Though for most purposes modern devices don't tend to need this level of micro-management or, indeed, worry!