How to preserve fine grain/noise when uploading to YouTube?

I have a project with that includes shots with very fine grain. (Synthetically added in post)

I have to export at a pretty high bit rate to retain the grain, though I notice when uploading to YouTube, my video loses a boat load of information. The noise effect ends up become mosiaced and creates muddy artifacts. I've seen content on YouTube that has similar shots, though without the grain distortion I'm experiencing, and seemingly having been re-encoded less harshly than my project.

How can I retain fine detail and maximum quality when uploading to YouTube/Vimeo, in specific, video grain?

Thank you