To add another wrinkle to your observation: the value "Health" is derived by dividing the battery's current capacity by its "design capacity" when new. The vagaries of mass production mean the ACTUAL original capacity of your battery may be greater or smaller than the design capacity. Thus, the value you see is based not on your battery's capacity when new, but on an AVERAGE expected capacity of all batteries of the model.
And we all know how averages work:

My M4 Pro Macbook Pro 14 that arrvied in late March 20215 showed a health value of 102%. I also have an Macbook Pro bought in June 2013 that still has its original battery. It shows just over 80%,and still gives very useable runtimes in use. Not bad for a 12-year old battery. The old Macbook Pro has not been "babied;" It has a lot of road warrior miles logged, and the only reason I replaced this year was software compatibility with older versions of macOS. I call that good service.
Please do not obsess over an inexact AND non-linear value.