How hot is your Fenix6 on boot?
There is no way to tell if this is just a calibration error or maybe a heatsink was not glued properly
But a swap out for another Fenix6 seems to be absolutely cooking itself.
It doesn't feel "hot" but warm and I cannot remember if the previous felt that warm.
Right after you turn on your Fenix6 after it's been off for hours, what temperature do you see?
75f degree room temperature, just turned on and it's already 86f degrees
Of course the Tempe shows entirely different temp, more accurate to room temp.
btw this widget is MTEMPE which I really really like, except for the color ring gauge which I'd rather turned off in exchange for larger font sizes
https://apps.garmin.com/apps/dd3e0666-b9d6-4b3a-9e98-672a256bc890
