Is a 92% battery health on an iPhone 15 concerning?

Your battery health is way above average. Most users experience about a 1% drop per month on average. That does not mean that every month will drop 1%, but some will drop more and other months won't drop at all. Keep doing what you are doing and enjoy your phone. You don't need to worry about replacing the battery until the battery health drops below 80%.

290 charge cycles

OK, thanks for the information. To keep things simple, let's say that it is 300 charge cycles.

The battery will normally decline about 1% for every 25 charge cycles.

300 charge cycles divided by 25 = 12%

So, by that measure, it would be reasonable to expect that your battery was now at 88%.

Your battery is really at 92%......so your battery is doing very well. It is above average. You have had very good luck with your battery.

Your battery will lose 1-2% in health each month. There is nothing wrong with the battery

Can you please check the battery settings again on your iPhone 15 and note the number of charge cycles that the battery has completed to this point?

With that information, we will show you a good way to know how well your battery is performing.

Personally, I think the 80% Limit is more of a gimmick than an asset, but that might be another discussion.