VRR/Freesync in Windowed Mode Buggy due to BitBlt Usage

tl;dr Someone needs to move FFXIV off the legacy BitBlt model and move the client over towards flip model, to fix many issues of Microsoft's own creation. Since FFXIV no longer supports Windows 7 in official capacity, this can be implemented.

ie, change DXGI_SWAP_EFFECT_DISCARD to DXGI_SWAP_EFFECT_FLIP_DISCARD

Microsoft's official take on the bad design of theirs, and subsequent update calling for people to use their new swap chain model: https://devblogs.microsoft.com/directx/dxgi-flip-model/

What is not mentioned, is that the "old way" doesn't just have a performance issue w/ windowed mode, but also prevents proper buffer tracking for VRR modes. This causes stutters to single digit fps in many cpu/gpu load edge cases. If a game completely goes bonkers with frametimes when using VRR, it's most likely not the gamedev's fault, but Microsoft's own API at the time of coding.

I do not want to use a 3rd party tool to wrap the d3d API to force flip mode, even if it does fix the issues outlined above, as it's against TOS to do so. I'm proposing this be worked on upstream in FFXIV's codebase itself.

Commenters, please be kind, it's not SE's fault... it's Microsoft's....

For relevant software & hardware specs...

uh...

Windows 10 21h2
R9 Fury GPU w/ 21.5.2 final legacy drivers.