Hi!
I went with the Asus Prime Z690-P WIFI D4. Its a good board, that supports PCI-E 5/4/3 and also has 3 slots for M2 drives. I also like the layout rgd the positions og the different connectors. Suits my case good 
(I have a NZXT 510i case). Note: This board doesnt support DDR5 RAM, so If you plan on going all the way, you probably going to need a Z790 ore similar)
Just to mention: Use a 13600KF (without the inbuilt ghraphics), 32GB DDR4 Hyper X ram, and an Asus Geforce 3080TI card. My HDD is one Viper and one Kingston KC3000, both PCiE4x m2s. I am very satisfied with my setup now. Running DX12 with TAA in 2K resolution, with almost all graphic settings on ultra. Have locked the FPS at 50% monitor refresh rate which is 30 for me, and FPS is constant, and frametime stable, anywhere I go in MSFS :).
(PRIME Z690-P WIFI D4｜Motherboards｜ASUS Global)
Freddy