It started to work when I changed to the following:
This is an aside, but I'm confused why the original method only let me type curly brackets... If anyone knows, thanks in advance for explaining.
Anyways, when I finally got it working, I wanted to test it by just typing the square bracket a bunch, and I would type it and backspace repeatedly, very quickly. I then noticed that the curly bracket would be typed again instead of the square bracket sometimes! I thought it was a problem exclusive to these brackets but I started trying the same typing and deleting with other shift+number remaps and a similar phenomenon occurred. I will just post my current progress here if someone wanted to test what I meant...
Also, just before posting this I noticed that this issue only occurs when my enter key is a hotkey for backspace. The regular backspace does not ever produce the same issue. Furthermore, I tried adding the wildcard on the hotkey and it made it so that instead of a curly bracket accidentally being posted an @ sign was posted instead. With the wildcard applied the key that shows up unintentionally is the key that used to exist there originally (i.e. since I press shift + 2 to get a square bracket, the @ sign sometimes shows up instead since that is typically what is produced on a QWERTY keyboard layout).
I also tried looking that the KeyHistory... but I couldn't figure out why the problem would be occurring (I understood what it was showing me, just not what to make of it since I didn't see a pattern in successful [ prints vs. @ prints).
; ~ ROW
(:: send, ]
; TAB ROW
; CAPS LOCK ROW
I am new to AutoHotkey and scripting and programming in general, sorry. Thanks for listening.