Those specs will run 4k fine I manage it on just rtx 2070 in msfs you won’t be able to max the settings of course but it will be good enough.
In my opinion unless your gonna be playing shooting games then anything over 60hz is a waste of time you won’t see much benefit if any. At 4k on those specs I doubt there will be many games with all settings turned up that will run much higher than 60fps anyway.