How the universe could possibly have more dimensions
String theory is apparently stuck in the trap set by relativity.
Many mistakenly claim we have a 4-dimensional universe.
The universe is infinite space with much stuff in it.
The universe has no predefined dimensions.
Any coordinate system and its dimensions are defined by the observer making measurements.
Relativity has the adage "“Spacetime tells matter how to move; matter tells spacetime how to curve.”
This cannot apply to cosmology though it could apply only in a very limited scope of the relativity's observer whose coordinate system is mathematically distorted IF their motion uses those dimensions being distorted. If the observer pushes an object to the left for some duration, the motion is unaffected by the coordinate system. Just as in the rest of the universe, all motion is affected by external forces including friction.
The video claims when I am moving my hand linearly it is really moving in a tight spiral motion which is too tiny to see. The video claims there are other dimensions to describe this motion.
The video also claims these extra dimensions are part of the universe.
The problem with these claims arises because it might be possible to describe this linear motion using various methods while the true motion is linear.
Absolutely nothing in the universe uses coordinate systems and their dimensions EXCEPT the observer who defined that specific coordinate system AND is using those dimensions to define points for the path of motion.
String theory might be interesting when it successfully integrates all the fundamental forces as claimed in the video but even then the universe still has no dimensions except those defined by the observer.