Batteries are considered Consumable Products. Over time it will degrade to a point where it needs to be replaced. The usage is normal as the capacity will go up and down all the time and never stay always at 100%. Apple Batteries are rated for 1000 Full Battery Cycles and / or 80% Capacity before needing Evaluation or replacement.
If you what to see via a Third Party Application what the Sensor are of the computer are giving out - Trusted Application from Reliable Developer - coconutBattery 3. Free to use or Paid for Added Feature.
Have a Stock M1 MBA also since March 2021 - Battery is just humming along just fine.
For additional reading on Battery and Apple Computers this link may help. About battery health management in Mac notebooks and especially for the M1 and Big Sur If battery charging is paused or on hold on your Mac
A feature introduced into Big Sur was to preserve the number of Full Battery Cycles - there was an Algorithm coded into the macOS. It is perfectly Normal for Big Sur to Pause / Suspend charging the battery beyond 80% and hold it at that level. One can nudge / over-ride this by clicking the Battery Icon on Desktop Top Bar and allow charging beyond 80%. From observations, it will Pause / Suspend again once reading 90%. Same procedure to over-ride and will charge to 100%
Further - profile showing Big Sur 11.2. That is out dated. The current version is 11.5.1 and fixes bug and Security Issue. Do a Time Machine Backup before attempting.