Graphics Settings Oddity

[Kartoshka]

I've been screwing with the graphics trying to get a good FPS without having the game look too bad, and I discovered something odd, and frankly a bit frustrating.
Basically, for some reason, it seems that combining TAA (high or ultra AA) with FSR2 results in the game looking sharper and clearer than default. This is weird because, individually, they both seem to have the opposite effect, making the game look worse than default.
A few screenshots will follow for comparison.

No AA, no FSR2 (default):
https://steamcommunity.com/sharedfiles/filedetails/?id=3124872884
As expected without AA, jaggies are bad, but overall clarity could be worse. Pay attention to the wires suspending the ceiling lights, and the "EVIDENCE LOCKER" words at the end of the hall.

AA, no FSR2:
https://steamcommunity.com/sharedfiles/filedetails/?id=3124873009
With TAA applied, the jaggies are reduced, but fine details are somewhat less clear. I would still prefer default to this.

No AA, FSR2:
https://steamcommunity.com/sharedfiles/filedetails/?id=3124873671
This is the worst, since it effectively lowers the resolution. The words at the end of the hall aren't even legible, and everything looks like a pixelated mess.

So TAA makes things a little blurry, and FSR2 just reduces the detail entirely as if you were on a lower resolution. Surely, logically, combining these two things should result in the worst picture quality yet, right? Only a madman would guess it might look as good, if not better, than the default picture, right?

AA, FSR2:
https://steamcommunity.com/sharedfiles/filedetails/?id=3124874124
This is with both enabled. It has less jaggies than the pic with just AA, it's clearer than default, and it doesn't appear to lose any resolution as would be the case with just FSR2. What is going on here? Why is a setting that's meant to upscale a lower resolution doubling as an un-vaseline/enhance button for the anti-aliasing?

So why is this frustrating? I seem to have found the secret method to having the game not look like it's made of legos while having no drop in clarity. And not only that, but it also doesn't seem to affect FPS noticeably.
The issue is the first person hands. I can look past a little TAA movement blur, but for some reason the first person hand/gun models shimmer like absolute mad when ADS with TAA enabled, to the point where they look like they are melting.

A few additional notes:
This only works with AA set to high or ultra, since lower settings seem to be FXAA instead of TAA.
This only seems to work on "Quality" setting of FSR2. Further settings have the results I actually expected.

So I guess I'm wondering if anyone has any insights on why the devs locked the best graphics settings behind an unlikely combination of bad AA, and a setting literally meant to make the game look worse for the sake of FPS. Also, can I get it to look like this without enabling TAA? I tried injecting SMAA with default settings, and while it is better, it's still more jagged and less clear than TAA+FSR2.