Well, as an update, I ended up buying a second module so I could rule out whether or not it was the module or the pi that was the source of the issues. The second module has the exact same issues/behavior as the first one, so clearly the issue is with the raspberry pi itself, and I unfortunately don’t have a second raspberry pi at the moment I can test it on. I tried a couple of different things now that it seems like the issue is on the pi’s end with the serial connection. I tried changing the baud rate around to 9600 instead of 115200, which had no effect unfortunately. I also tried running jumper wires to the module instead of plugging it straight into the pi in case there was some kind of signal noise/interference. That didn’t end up making a difference either.
Any suggestions about where to go from here? I could try switching the uart to different pins which I think is possible to see if that changes anything.