I have a 2005 RAM 1500 SLT with 86k miles. 4.7 slt 4X4 QUAD

My Ac Blows cool air not cold on hot days. I have added a can of freon but still the same results.
front cold air IS about 50 degrees. All the vents work top and bottom.

WHEN i first got the RAM it was so cold on long drives it would freeze up and would have to pull over so it would un freeze.
I was able to find a bulletin on a fix for the freezing was to add a resistor in series with a wire on the ac controls to slow down the compressor to cycle on off more. That helped on the long drives.

But getting in the RAM now and just seems it could be colder.
The compressors stays on pretty much not much cycling.
Added 1 can of freon not much difference in temperature .
I measured with a digital thermometer and at the vents about 50 degrees.

Checked pressure with gauges and the low side about 37 and when compressor kicks in goes down to about 22 then back up to 37. High side was around 200+

Just cant seem to get the ac to get colder!!!!!!!!!!!!!!

Any suggestions??