I really do like your idea of a 5th dimension being a second time dimension. However I don't like this an analogy. "remember" means something and it is not space. (Maybe 'remember where you have been as one place but not two.')

I do not like entropy as 'the arrow of time' ... it might be a correlate but it is not obvious it is a cause. And the idea of the 5th dimension being time with no entropy reduction implies that it accounts for simultaneous action at a distance, not going back in time.

just say'n.

That said, I can imagine how you can do the math with a 5th dimension. But it would be nice if it also makes the physics more sensible. This is why I like Wolfram Physics where things like Planck length are not the smallest quantum of space and the universe computes itself forward in time (for its real arrow, entropy just being a correlate). The 5th dimension in Wolfram Physics could be a way to compute a time transition like it does with regular spacetime. But then, I think, you need a sixth dimension which is a space time in order to compute yourself into the past. As they say...