Was able to resolve the issue. In the end, not exactly sure what was wrong and caused the Z-Axis to lock up and not be able to move, but what fixed it was breaking down the printer all the motor and reassembling it.
More detailed breakdown of fixing process: As the X-Axis linear rail was locked too low for me to remove the heatbed, I could only remove the bottom faceplate for the Z-axis belt (I did also loosen the belt but the rail was still locked). While there was a ton of resistance in the belt, with enough force, I was able to get the belt to rotate just a little bit. After that, it seemed to be able to go down (albeit with a lot of force), but wouldn’t go back up. I remembered reading on a forum with a similar error code on z-axis moving how someone was able to get there’s working again by manually moving it down a little and that seemed to reset it. So, I thought I’d give it a shot and see if that was enough to unlock the rail and get it moving via motor again. Sure enough, I could now control it again with the control screen! But there was a new problem. As it moved up and down, it would make a buzzing/grating sound followed by a click and repeat (buzzz click, buzzz click, buzzz click…) coming from the right screw (possibly down in the motor/belt area). At least I was able to get the X-axis rail moved all the way to the top so I could clear the heatbed and check the motor.
I secured the X-axis rail to the top with zipties and fully disassembled it again, all the way down to the belt and motor. I removed the Z-axis belt and inspected it for any nicks or breaks. I checked all the gears and could not find any obstructions (nor anything blocking the tension holes). I then removed and examined the motor, checking the interior and manually spinning the rotor. With the top of the motor casing off, the rotor did make a duck-like noise, but this went away after I put the casing back on and it spun smoothly. I honestly couldn’t find anything at this point and just put it all back together with hopes and prayers to the 3d printer gods… Plugged it all back in and EUREKA… it worked just like new. Recalibrated with no problems, printed a Benchy just to be sure, and everything seems back to normal.
Maybe the 3d printing gods were merciful and took pity on me. I’m just glad I was able to get humpty dumpty back together again and that it’s working. No better way to learn your machine I suppose than having a problem and having to take something apart.