Will charge 2021 iPad Pro 12.9 5th gen over 80% damage battery? Myth or Real?

I’ve seen many post people saying new iPad Pro can charge over night (100%) without damage the battery and I heard people says don’t run the battery to 0% and don’t charge over 80% as it will count as 1 cycle charge and the more cycles the faster it wear down the battery life because Lithium batteries have memory stores for charge cycle.

Again people says it’s myth but my question is then why some electric car company have a app on your phone to have option to stop charge after it reach 80%. Those batteries are Lithium too. What’s the differences between the two batteries?