HVAC condensation

I have a 2 story house in a humid SE Texas region and my hvac units have been sweating for the last 2 years roughly. Both of the systems are 6 years old and I am experiencing a lot of condensation on both of my units.

I’ve had to have the drain pan replaced on my first floor unit and I’m constantly having water spots in one of the rooms upstairs and a bathroom vent. The bathroom never gets used so no shower or hot water running while the fan is not on. I had an AC tech come out and check the whole system and everything was in good shape. The whole units are sweating on the return and exhaust plenums (sorry if I didn’t say it right. I’m not a AC tech and don’t have any knowledge of it I’m just a defeated homeowner looking for guidance) and condensation is forming on the outside of the ducts. The AC tech suggested to put in an attic fan to help pull the humid air out and while it’s helped a bit I’m still experiencing the same issue. Not to the same extent but still enough to constantly keep dealing with the water spots.
At this point I don’t know what to do with this anymore and how I can get this fixed. Any help or advice would be greatly appreciated.