If I were you, I’d go straight to 9800X3D / AM5 platform. As the others said.
If cost is a factor I’d save money until I could do it. I definitely wouldn’t be going 5800X3D or 7800X3D now. 5800X3D / AM4 is end of life tech. It would be ok (5800X3D is no slouch in MSFS, even today) if you absolutely can’t spend the money on newer tech (AM5/DDR5), and don’t mind not being as future-proof (AM4).
7800X3D is right out, to quote Monty Python. You might as well go 9800X3D if you’re going AM5 / DDR5 now.