I understand newer iphones now have the option to only charge up to a certain percentage. Mine doesn't have that, it only has the "smart charging", which tries not to charge it too quickly and only is full by the time it expects you'll use it (usually in the morning). It's very hit and miss for my use patterns, so it ends up at 100% most of the time...
But yeah, at some point we should also consider the tradeoff between convenience and battery life. Batteries can be replaced, having to charge twice a day is a PITA for me.
One sits on my desk at work, one sits on my desk at home and the third sits on my bedside table (it acts like a clock radio / alarm clock). I just place it on the relevant charger while working / sleeping and it's always got enough charge when I need it.
(I also use the surprisingly fairly recent addition of charging protection to limit it to 80% charge)
I'm aware this won't work for all use cases, but it's great for mine.
The only time my phone has given me a message about heat was, indeed, in a phone holder in the car, but it wasn't even charging. We are experiencing a heat wave in Australia right now though, and the car had been sitting in the sun in a car park for an hour.
But, I figured that the battery would heat up more the faster it's being charged, and so wired charging at the same wattage would heat the battery more than wireless charging.
Must be a lot of power->heat transfer loss with wireless charging.
/s