Seasonic PSU calculator shows 750 to 850 minimum
Bequiet agrees with it. https://www.bequiet.com/en/psucalculator
Coolermaster PSU calculator never works for me
if you used the Corsair calculator you could be more specific - https://www.corsair.com/us/en/pc-builder/psu-finder/case
You need to be able to account for spikes. The 30 series can sometimes ask for more power than they say on the box, and its only getting worse. Better to have more than you normally use.
850 still has 60% load with your set up so its a shame PSU makers don't make 900's, they all jump to 1000.
If you ever plan on getting a better GPU at some stage, you might be best getting a 1k watt PSU now, something from Corsair or Seasonic would do trick. You want a good brand as some brand have PSU that say they can do X watts but are often way below. If its a good PC, it deserves a good PSU.
PSU only use the power they are asked for. Just because its 1k watts on box doesn't mean it uses that much. So buying a bigger one won't cost any more in long run.