I charge my 14 PM exclusively via MagSafe (via desk, battery pack, and car charger) and my battery health is at 100% since launch last year.
My 13 PM after a year, was also at 100%. The key I’ve found was only rarely charging it past 80%, or rarely letting it drop below 20%.
This is so funny. Long time ago we used to think full drain ‘reconditions’ batteries, and that we should do it once in a while.