Don’t stress so much over it and go ride.
You’re in the right ballpark, but there are a ton of variables here that make it hard to have a specific recommendation.
Basically without a lot of fancy testing equipment for your setup specifically, nobody will be able to tell you exactly what pressure to run given your tire/wheel/weight/road condition combo. You’d have to spend a whole bunch of money to save like 1-2 watts?
Basically what I’m saying is you’ll never know, so why get stressed over it. It’s close enough. Let it go.