coconutBattery.app on macOS connect your iPad via USB -- unless someone else has said it. Pulls all the iPad battery data, including manufacturer, total age, cycle count, and capacity, and health.
I think Apple wanted to originally remove the need to obsess over battery health, by lowering the iPhone clock speed to account for battery loss. Until people got upset with that, and made a lawsuit out of it.
Personally, I had no issue with my iPhone or iPad running slower, but still giving me 18hrs of battery life, for example. No need to play a intensive 3D game with my battery at 18% like all the online-screaming bad battery performance vids.
Now though, my iPhoneSE2020 with 99% battery life after 8 months, is doing fine, I use a hardware timer-switch so the phone only charges for 15 or 30min at a time, never running over or needing Apple's software, and keeps between 80-20% respectively.
Good luck!