Iphone 12 mini temperature warning on screen - bug?

Hi,

I can't get my iphone 12 mini out from the temperature warning screen: i didn't use it all day today while at work, just when tried to unlock to make a call, message was on screen, phone was at room temperature - later at home attempted to restore & update iOS connected to my laptop - no bluetooth or wifi connectivity working either. Reset seemed to work but didn't get to initial set-up stage, temperature warning on screen interrupts it.

Has anybody have this issue? How did you get it to work again?

Thank you