Finally upgraded my setup enough to warrant posting an update!
I'm definitely not regretting that second monitor. Such a massive QoL improvement in so many ways. It's also so large that it wouldn't fit under the shelves that used to be on top of my desk, so I had to remove them. Got a Kallax unit from Ikea to make up for the lost storage space and I'm also very pleased with that purchase! Still need to get some proper bookcases soon, though. The two tiny ones I have are still overflowing even after moving all my mangas and art books over to the Kallax...
Also, I think I finally need to upgrade to some proper PC speakers. That bookshelf stereo has served me well over the years but they're getting hard to fit into this new configuration. Also, I think the stereo part of the thing might be fucked lol.
I was doing some reorganizing and found some of my old CDs and put one in it for the hell of it. The disc tray was somehow covered in dust even though I haven't opened it in years and even after wiping it clean it would only play the first track. When I tried skipping to the second one, it stopped playing and started making some weird noise. I panicked and got the CD out and there was now an inch wide ring of dust on top of it. Now it just won't play at all lol. At the very least the CD player probably needs a deep cleaning...