Well, my server is now simply dead, how lovely.
Eventually, I got a notification that an outage was reported for my server, ps153667. I reported the outage over 24 hours ago, yet it was marked as being reported just a few hours ago. It's also marked as resolved 45 minutes later, which it isn't: the server is simply down altogether.
For the price I end up paying due to constantly bumping the RAM up (to even 4000MB, thinking the issue was on my side and that I needed to investigate) + my revenue losses when the server is down for an extended time (I would have had 2 ad campaigns going live today), I guess I should simply move my toys over to WP Engine.
What's most disappointing, though, is not even the downtime and the frustration. It's the failure to simply acknowledge the issue, as a simple "we're working on it" update would have been enough. Claiming that the issue was only reported a few hours ago (instead of 24 hours ago) does not help, either.