Worth a change at the apple store?
Everything you said is true. I used to have some bad battery ocd. I gave that stuff up and just charge to 100% every night. I had an app on Android that warned me once the phone had charged to 80%.Never charge it to 100% and never leave it plugged in overnight. Avoid if at all possible discharging below 20%.
Apple's battery care recommendations had to balance convenience and device run time vs battery longevity.
They have zero incentive to keep a battery healthy for 4 years or longer.