Thanks for replying.
I do indeed know what I'm doing. This particular problem just has me stumped.
As I mentioned, I am working my way through the relevant parts of the Arch Wiki, because, as you say, I'm a person who tries to RTFM. I was posting here to see if anyone had some across some specific issue that I may have missed from a recent update in the last few months. Wasn't looking for a replacement to RTFM; was looking to see if there was something specific I might be missing.
As for logs: This is the link to the when the problem began, back when I was under the impression that it was a hardware problem (specifically the power supply) I know now that it's not a hardware issue, but the logs I posted in the comments still apply.