Keyboard keys only work in game?

Hey y'all! I got an ASUS Rog Zephyrus G14 laptop about 2 years ago. Haven't had any keyboard issues with it until last week starting on Nov 2. I haven't installed/updated anything beforehand as far as I know, unless it installed an update when I went to shut it down.

The problem: "D", "+", & backspace keys all stop working at random - one minute I'll be fine, and then next I'm suddenly D-less for the next 8 or 9 hours. These keys work if pressed in conjunction with another key (ex: shift + D, or ctrl + backspace). I also have no issue in video games using WASD to move around, or binding a control to either of the other keys & using that. However, I still can't type normally in in-game chat boxes. Since it still works in video games, I assume it's not a hardware issue...?

I've tried:
- checking to see if sticky keys was on (it's not)
- trying various function lock combos to see if I'd locked something somehow (i haven't)
- normal restart
- clean boot
All to a tragic lack of effect 😔.

This is driving me crazy & really making me realize just how often I use D & backspace, & I really don't want to live out the rest of my days having to copy paste lowercase d into my sentences, or worse, having to replace this laptop before it's even 2 years old, so I welcome any insights that y'all have!

tl;dr D, =, & backspace keys will randomly stop working for word processing but are fine in video games.