The scaling itself in the game depends on HOW its performed.
Per-Pixel scaling is the least costly and maintains “pixel perfect” sharpness as long as the scaling is an even equivalent to the panels native resolution.
Integer scaling is most processing costly but is also a balance in sharpness (slightly blurry) and can sometimes hide artifacts that are inherent with different graphics settings, especially with AA where shimmering is a problem.
There are some other methods of scaling but Per-Pixel and Integer are the more commonly used and what I know.
For me, overall while in the Cockpit, everything is relatively blurry on the edges especially with the analog gauges and I think a lot of that has to do with how they made the assets. If I crank the resolution all the way to 4K with no scaling, they look almost perfect at the default seating position. Any lower and they start to become a bit fuzzy with some slight shimmering.
This leads me to believe the scaling is Integer based and why OP perceives a sharper image at native 4k with 50% scaling. But also without knowing what the rest of his graphics settings are, we can only make a guess as to why that is as they all play a part in the overall look regardless if we wanted to debate about resolution scaling and pixel counts.
In any case, OP has a choice to make that only he can make for himself that i’ve already listed