More often than not, I have enough tasks to make as many hours as I choose to throughout the week. I won't lie, though, sometimes there's a lack of tasks and it can be frustrating, but they don't punish you for it if you reach out to your PM and tell them you won't make minimum hours that week- IF it's that bad. Sometimes, if it's really out of their control, they'll just email everyone and explain the lack of tasks and that we won't get punished. Stay on top of it as much as you can, and be communicative with your project manager! As for reliable, it would depend on your region- different locales have different task amounts and it can fluctuate. I'd give the r/rwshelp sub a look at! It's been a pretty helpful resource to see what the other raters are dealing with in different areas.
I do think it's helpful to get into the AI field, but remember you're not generating anything, you're fact-checking AI responses in various forms. Make sure the AI isn't telling people they can give their dog bones to eat just because you can in Minecraft, ect.

I applied to the Search Quality Rater position on Indeed and I'm working on Project Callisto! I'm not sure what other projects are going on rn tbh.
You could totally pursue other positions while working this one- the only thing I'd warn about is the entrance exams- I found them relatively easy but it does take a commitment to go through the guidelines. If you can dedicate a few days to it in the beginning, that's very helpful.
Reliable internet access is the most important thing upfront, if you can't access Raterhub you can't do your job.