iPhone 15 Pro Battery Drain

I’m sorry, I don’t see your problem. If your older phones were at 98% after a year either you are a very light user, or the battery in the phone exceeded Apple’s minimum specifications. And I don’t understand your screen shot.

Your Maximum Capacity appears to be 96%, with a cycle count of 252. The iPhone 15 battery, with an expected life of 1000 cycles to 80%, will lose 1% for every 50 cycles. 252/50=5.04, 100-5.04= 95, so your battery is doing slightly better than average.

But I don’t know where you heard that charging from 20% to 100% is optimal; What is optimal is charging overnight, every night, with Optimized battery charging enabled. This will charge to 80% and hold, then finish to 100% around the time you start using the phone in the morning. An alternative is to use the settings on the iPhone 15 to limit maximum charge to 80%; this MAY provide some minuscule benefit on the assumption (unproven) that charging to 100% can shorten battery life.

But in reality, you have almost no control over battery capacity management, and there is only marginal benefit to paying any attention to charging at all. The one thing you can do to damage the battery is to routinely let it go to zero, and not charge it immediately. So don’t worry about the battery, and just enjoy the phone.

Here is a very long discussion of iPhone charging practices→When to charge your iPhone or iPad | Communities

Everything looks absolutely normal. The battery on the iPhone 15 is expected to last 1000 charge cycles before the Battery Health reaches 80%. The drop you experience is not going to be linear and some months will not drop at all and other months will drop more, they are simply averages. This is an increase from previous models that were designed to be 80% after 500 charge cycles, so there have actually been improvements made in this area.

iPhone battery and performance - Apple Support

With you showing 252 charge cycles, your Battery Health would be expected to be 95%, so currently it is showing better than average, but how averages go, you should expect that next drop shortly.

Keep doing what you are doing. For a device showing 96% Battery Health after a year, that is exceptional and it would appear that you are bragging. Many others would be jealous.