omg I got it working!! I found the log setting and was able to turn on debug, and combining that with reading the code, I was able to determine that I simply hadn't allowed a tolerant enough "Maximum load average"!
Apparently, this checks the average number of processes over the past 1 and 5 minutes, and if it's above the set threshold, then it won't run. Since I'm on a shared web host, of course this won't be lower than the number of users they put on a server, which is apparently more than 20.
Setting this to a number higher than that has allowed the worker to run, and it's actually working now!! ?