How would one go about "opening" the 4th dimension? aka making it accessible in some way?

how would one go about "opening" the 4th dimension? aka making it accessible in some way?

Math.

Have you ever considered the possibility that you don't actually understand the scientific terms you're using? That maybe all of the advanced scientific explanations you've ever heard have just been metaphors, oversimplified to the point of removing all useful information? And that, therefore, you not only lack the knowledge to answer the questions you have, but also to know what questions are even vaguely coherent?

I would strongly recommend looking into this possibility.

you'd die instantly, your guts would be ejected into the 4th dimension

so why are there specifically 3 spatial dimensions

That could be just an approximation on a given scale.

There's only 3 spatial dimensions because the universe has 3 spatial dimensions.

It's that simple.

Theres a paper that studies the stability of spaces with higher dimensions and more than one time dimension and most of them are unstable

Point an arrow in some direction

Find a second direction at a right angle to the first

Find a third direction at a right angle to the first two

Find a fourth direction at right angle to the first three

>more than one time dimension
what does that even mean?

Psilocybin works.