Both of my M2 iPad Airs have the 80 percent charging limit option. So does my new Mini that arrived today. I‘ll try using the 80 percent option on the Mini (I do on the Airs) - just to find out how long the battery charge will last for me.
BTW, I have been using the 80 percent option on my iPhone 15 Plus since I bought it new a year ago. Battery health is 100 percent and the phone shows fewer than 50 full charging cycles - despite my charging it to some extent everyday.
But… I have to wonder sometimes. More than once, the phone has charged to 100 percent despite it being set for 80. And there have been other times when the phone indicates it is charged to 80 percent - then switches instantly to showing 100 percent charged as soon as I turn off the 80 percent charging option.