My 15 Pro battery is right at 80% health with over 1000 cycles. Apparently it needs to hit 79% before AppleCare will replace it :/ Anyway, I find Low Power Mode is super helpful if I’m gonna be away from power for a chunk of time.
edit: it FINALLY hit 79% so I could get the battery swapped out free under AppleCare. Weirdly, I didn't get any kind of alert when it did, though. Had to notice it when I checked manually.