14 Pro Max at 88%. I’ve never had battery health degrade this quickly on previous iPhones, and I’ve had every iPhone since the 6. I don’t recall percentages on my XS and earlier, but I know that my 11 Pro Max was at 99% when I got my 12 Pro Max, and it was at 98% when I got my 13 Pro Max. My 13 Pro Max was at 93%, when I got my 14 Pro Max, and the only thing that’s been different in terms of my charging behaviors is that I’ve used MagSafe charging much more. Maybe the heat wireless charging creates is worse on batteries, but I’ve read others using MagSafe not have this problem, so I really don’t know unless Apple has tweaked the way they report battery health.
EDIT: Now I’m at 86%. It’s dropped 2% in a little over 2 weeks.