the charger (magsafe?) from the apple watch ultra does not work on a iphone 13 max pro?

I got a iphone 13 max pro.

If i place the magsafe charger on the back of my phone (i feel that it sticks on one spot because of the magnetic ring) it does not charge.

On any other wireless charging pad my phone will charge. I do not have a protection case/flipbook/bumper or whatever around my phone.

i also noticed that if i place it on the backside of the phone it will magnetic connect, but it falls of easily within seconds.

so is the magesafe charger of the apple watch different then a magesafe charger of the phone?