How can I disable auto calling after hanging up calls on my iPhone SE?

check the call/phone settings .

to make it easier make all settings to default .

once done restart the device .

If you are still facing the issue then take data back up and erase the device followingly do iOS reinstall.

This usually happens when you tap the red button just after the call hangs up automatically and you end up tapping a contact either on recents or favourites.