If rebuilds are on the table – isn’t the 7800X3D preposterously good at Flight Simulator 2020? My understanding is it’s something like 30% faster than anything on the Intel side.
I’d definitely wait for the final microcode update, FS 2024, and 9800X3D to see how things shake out.
I say this as someone with an hp reverb, 4080, and who upgraded from a 12700K to a 13700K just before the 13th/14th gen stuff hit the fan* 
It was such an easy upgrade (drop-in CPU replacement).
Unless the 14900K is a stellar deal, for about the same cost I bet you could probably get the 7800X3D CPU with a motherboard and RAM.