Just a note to say that I have the exact same issue as the author in Freeform on my 13 inch iPad Air. It heats up to the point that the screen dims, and then dims again and the iPad is uncomfortable to hold. It doesn’t take long for this to happen either.
In contrast, the iPad does not overheat when painting for extended periods in procreate.
In contrast, the iPad does not overheat when painting for extended periods in procreate.