overheating and now unresponsive

i have had this problem multiple times now where my phone has had a temperature notification come up and the phone has been very hot, however, whenever this has happened the phone is not being used. i keep getting the same advice of leaving it to cool down and then charging it and waiting for it to turn itself on, this worked the first time yet this time it hasn't changed since 11am this morning and it is now 7pm and it is still unresponsive. it is a new phone and was brought when they iphone 11 first came out but i have only recently just started having this problem but it is now a recurring problem and is becoming a bit of a nuisance, so any help would be appreciated.