Monitors - Which monitor?

[N1V2GU]

I’m looking at replacing my LCD monitor on my FlightGear computer. It is old and having some problems that are harbingers of impending death. It’s 23 inches diagonally with a LED fixed pitch grid of 1920x1080 pixels. With Windows, you can fiddle with display properties to set over-size (things look smaller), under-size (things look bigger) or go totally native (happiness). In rummaging through the Forum, I see several statements that lead me to believe that FlightGear chooses native resolution period. Eliminating the need for a scaling engine is CPU/GPU efficient, but operationally it leaves me with questions.

Indulge me for a moment while I describe a scenario, I will get to the questions. My FlightGear is setup for the Fairchild A-10 Warthog. It’s spooled up and ready to go; my view is pilot’s seat forward runway level. I have adjusted my view such that the HUD’s frame ears are touching the screen top. The left and right monitor edges bracket the cockpit frame. The lower edge of the screen cuts across fractionally below the four gauges L&R Temp and L&R Fan Power. If adjust my view to see all the gauges, I have no acuity for visual flying. If I align my view for VFR then I lose the instruments. Yes – I can toggle up, down, left and right but I get vertigo. Darn – I’m stuck in a rectangular tunnel.

So in considering a new monitor, physical size is irrelevant because the fixed pitch grid determines what I’ll see.
If the new LED monitor offered a finer grid, what would be the effect? Say I chose 3840x2160, the aspect ratio is the same but there would be many more pixels available.

Questions: Using the scenario above, but with a 3840x2160 monitor:
1/ Would FlightGear maintain the tunnel by orienting the four viewing corners to the same places that I see now in the cockpit? In other words, the view is the same.
2/ Would the viewing tunnel increase (see more) or decrease (see less) of the area that I see now?
3/ Does image detail granularity change at all with more pixels?
4/ Are there magic parameters to adjust this perceptual tunnel size?

Thank you for taking the time to read my missive
and heartfelt thanks for any comment, pointer or solution.

Jan