My wifes ipad mini 5 running hot since 18.5 update. As in hard to even hold hot. Its whenever she uses it, or charges. Not hot while asleep. Doesnt matter what app she uses.
Is there excess Wi-Fi traffic? My iPhone would get very hot when I played a certain game. When I played the game with Wi-Fi turned off it didn’t heat up (I don’t allow cellular data for that game).
I've come across this with my Mini 4, the only sure fix was to connect to my Mac, backup the data, wipe and reinstall a fresh copy of iOS. Looking through the logs and talking to Apple support but never figured out what was the root cause.
One thing you need to have is a USB multimeter . They are cheap you can plug one inline on you iPad Mini. It will tell you voltage, amps drawn, and Watts. Here is a $35 USD example. They are dead handy for checking how a device is charging.