How to disable the main Viewport for a multi monitor setup?

I have 3 monitors and so when I do stuff in Unreal Engine, I generally open another, dedicated Viewport and move it to another monitor.
I’d like to be able to completely close the main viewport. What I generally do is I drag the toolbar up as far as it goes, and disable its realtime
But I still can’t completely disable it, and even hide it.

Is there such an option somewhere? If not, I’m sure many of you have multiple monitors, so then what do you do in your setup?

Please, share your thoughts
Thanks in advance!