Brand new tires are likely to still have some of the mold release agent in/on the tread rubber. Don't expect them to perform as intended until you've scrubbed it off. This should occur within a couple hundred miles of normal driving, and that's arguably the better way to get this done. Get this done and see if the problem goes away.
There isn't enough information for me to suggest a different rear tire pressure.
'08 GT coupe, 5M, wheels, tires, pads, fluid, a few suspension mods . . . still almost stock height
'19 WRX, 6M (the "family sedan")
'01 Maxima 20AE, 5M (the spare and occasional winter driver)