Go here https://silca.cc/pages/pro-tire-pressure-calculator

I use the oldshool tire sag to adjust my pressure

If you're worried about it, start at 50 and work up 5 PSI at a time until you find what you like best.

Being on the chonkier side, you should probably start on the higher end of the pressure range. You really want to avoid the tires bottoming out and hitting the rim while passing over obstacles. That often leads to punctures. Once you've established an upper bound you can work your way down to the kind of comfort level you like best. Less pressure means more comfort but also more rolling resistance. In short, there is no right answer. Just start with something reasonable and experiment.

65 PSI. But go to just below 70 because some will rush out when you take off the pump. If it's too firm, you can easily let some out while you're riding. Much harder to put the air back in.