Test with RTX3090 and Ryzen 5900x

no, it’s using hardware in a scenario it’s not optimized for.
A ryzen 5900X is a processor that’s great for productivity tasks (rendering, 3D modeling, video editing), there are no games / sims out that utilize all those cores/threads.

An RTX3090 is designed for high resolutions, and is seriously overkill for 1080P.

Build a PC with hardware that fits your usecase.
Sure, the sim can be optimized, but don’t expect any game or sim to fully utilize hardware that was designed for other types of tasks.