This started worth talking about notation. Notation of mathematics has changed significantly over time - Newton's Principae is not readable without accounting for changes. In the history of maths, that is a fairly recent work.

I actually agree with your premise: mathematics and it’s notations (plural) are ancient. The current notations are those that were found to be most convenient by centuries of practice by expert practitioners.

This is of course very true but doesn’t take into account invention of computer that is relatively recent.

Since it in principle never makes mistakes (in practice there are of course bugs, but they are usually different in nature than human errors) it changes what is possible and most convenient. You no longer have to optimise for simplicity as heavily for example. On the other hand computers basically can’t deal with ambiguity, so the rules and statements have to be stated very simply and clearly.

I believe computers can change the landscape of what’s best notation. This is an interesting, interdisciplinary topic to explore.

I think APL was originally created as a fix to this problem. A completely revamped math notation to make it more fit to computers as a medium, instead of pen and paper.

If it was created thus then it could hardly be considered successful. To all but the dedicated and obsessive cognoscenti APL is nothing but gobbledygook.