Do you discharge your iPhone all the way to 0%? The bottom 20% are also not so great for battery wear.
Ideally you would stay between 20-80% (only charging to 100% and discharging to 0% when you really need it)
I try not to but it has been below 10% many times (and occasionally so empty it turns off).
Now WFH, so it has been plugged most of the time since late March and I'm really just nursing it through until the newer phones are released so I can decided whether to get the updated SE or the newer model.
My 2015 13" MBP has been charged 221 times in 4.75 years. It has been plugged in for the vast majority of the time, yet still shows 88% total capacity and will still last 8+ hours doing standard web dev stuff.
My iPhone gets discharged every day, but its capacity is down to 78% after just 2.5 years.