New Rheem 3 ton unit

Hello, I'm located in the New Orleans area. Just recently had a brand new Rheem 3 ton unit installed in my 3 bed 2 bth 1542 sq. ft home. No supply vents in the bathrooms, nor the laundry area. The home has a 3 ft slab elevation and ceiling heights in the bedrooms are 8ft, and in the living areas are 10ft. The previous unit installed was a Heil 3 ton unit, and it cooled sufficiently throughout the house. I've had the AC tech looked at it several times since installation, and he has stated that everything seems to be working fine with the new unit.

The air handler is installed in the hall closet nearest to bedrooms. I measured the closet supply vent and it read apprx. 57 F, and the farthest supply vent from the air handler read 59 F. The return vent measured apprx. 71 F. The unit seems to run a lot longer to get to the setpoints if the house is 2 degrees warmer than the setpoint. Even at night, the unit may run 2.5 hrs to get to 74 F to 72 F. The bedrooms seems to cool fine, but the living space seems to struggle. The humidity level has been about 58% or higher since installation of new unit.

I'm wondering if I'm undersized, or do I need to attempt to mitigate the heat and moisture by insulating my crawspace, and adding more insulation to my attic space.

Thanks in advance,
RJ

Unit Info:

Condenser Model: RA1436AJ1NA
Air Handler: RH1P3617STANJA
Thermostat: Vivint Nest Thermostat (located in hallway, center of home)

source https://hvac-talk.com/vbb/threads/2241156-New-Rheem-3-ton-unit?goto=newpost