Having a starting point to adjust from makes life easier, whether using a fit calculator for seat height or in this case a tire pressure calculator. The only thing almost certain about using the max inflation spec on the sidewall is that you will experience a harsh ride, unless by chance your weight/tire combo happens to fit at the max range.

This is a widely recommended calculator:
Bicycle tire pressure calculator

Use the middle one....the one with the weight of the fully dressed bike and rider. You can input your weights, tire width and it has a few different ft/rr pressure drop rates.

It will be a much better starting point for a comfortable ride than the sidewall.