In all honesty I gotta say I haven't lost any capacity after 1 year. The BatteryBar app shows 0.0% Battery Wear of the available 44,220 mWh.
But that still gives me the same lame 4 to max 5 hours autonomy.
And that's with the latest updates finally installed (Windows 2004 and 20H2).
If I could I would give this back I'd get the new MacBook Air. I'm not an Apple fanboy, but with the same money you get 2 days autonomy, better performance and better screen...