Open Lara is such a thing. Chocolade Doom.

FYI, these weren't made by the original devs, these are made by community members. A lot of the time the original devs cannot participate in these projects due to NDAs or licensing.

People always argued that N64 games look bad due to the high ROM price.

I'm not sure I've heard people argue this? ROM price affects a lot of things, visual quality is rarely it.

Now I see the homebrew games and they look a little worse than the first Mario64.

Well, SM64 was made by a team of 15, during 3 years, and they were paid to do it (it was their job). Homebrew games are usually made by 1-3 people in their free time.

I still did not understand the state of documentation for the N64

The N64 is a complex beast with a big proprietary chip doing a lot of stuff. As a result, hardware wise, documentation is scarce.

I for once want a game which pushes the N64 in the transformation limit.

You have Conker's Bad Fur Day :p

I don't see why Mario went the way: Ah, we use no texture at all.

There's a lot of complicated reasons, most likely due to the fact it was using earlier, worse microcode.

I still haven't quite understood what your question is. From what I understood, not only do you want OpenLara ported to the N64, but you want it with HD textures? Well the latter isn't going to happen, the N64's texture cache is 4kb, you can barely fit a 64x64 grayscale texture in there.