I have three screens as the main display and three touchscreens running air manager for instruments. Air manager is not free, but it’s well worth the money.
Normally the Garmin glass cockpit screens are popped out to the precise positions needed using popoutmanager, which is a free addon from flightsim.to
My pc has three displayport connections and one hdmi. Another hdmi is connected through a usb3 to hdmi adapter and the last one is an android tablet connected through Spacedesk, which is a free app.