I don't know if this will help, but you might want to try it in case it does.
Go to Settings > Display > Screen Timeout. Make sure "Keep screen on while viewing" is toggled on.
The phone will now use the selfie camera to periodically check to see if there's a face looking at the phone. If it sees you looking at it, it should keep the display turned on and not dim it.
Alternatively, you can make a Routine that changes the timeout to the longest setting if your phone is charging.
Go to Settings > Display > Screen Timeout. Make sure "Keep screen on while viewing" is toggled on.
The phone will now use the selfie camera to periodically check to see if there's a face looking at the phone. If it sees you looking at it, it should keep the display turned on and not dim it.
Alternatively, you can make a Routine that changes the timeout to the longest setting if your phone is charging.
