Yesterday, 22:07
I don't have any experience with the latest Ryzen, but I can tell you that with the 13900K and 4090 combo is wonderful for MSFS. I run a 5,120x1,440 display for 2D MSFS, and a Reverb G2 for VR, and both are silky smooth. 2D is Ultra-everything and 200 LOD and a Tobii Eye Tracker; VR I have a couple of things turned down to High that don't look visually different and details at 150.
And I have an MSI Z790 board in my SFF secondary system and it's rock-solid.
So if you don't want to wait, I can't promise that the AMD chip won't gain you a few FPS here and there, but i can tell you that the 13900K/4090 combo will deliver plenty to make you happy!
Also, on the Intel build, at least, you don't need 1300W. If that's all that's available, it's fine, but I'm running 1000W and it's got...