So ever since the Mario 64 PC port, there's been a team attempting to change all the models to fan made SGI-like render like the old promo pictures (See first picture of Mario fighting Bowser) and they've been extremely successful at it
Paired with the 16xre-upscale mod, it looks phenomenal
I reached them on Twitter, it seems that remodeling every levels to make some parts less flat is already in the works. It's going to be perfect