In the morning, before starting, when the system is stabilized
so that suction side pressure equals compression side pressure
This is what I read on the suction side (i.e. it will be the
same on the compressed side).

Why do you assume that each side of the system is the same? You've got a
pressure gauge on one side. Your problem is consistent with the high
readings that you have. Do you really have any idea what the pressure is on
the other side?
I'd consider that the refrigerant is contaminated. Go through the
cleaning process, pressure test and replace the refrigerant. If the problem
comes back suspect a leak or a bad compressor.
Hope it turns out to be an easy fix.

Dave M.