Hi there - I'm on Rover, partially for the cash and partially because I like hanging out with dogs and want to keep my own dog comfortable around others. I typically clear a few ($200-500) hundred dollars per month (before taxes), with the summer and winter holidays being the most lucrative. I'd imagine this varies a great deal, though.
I get plenty of requests, but I only accept bookings when I feel totally comfortable and know for sure I don't have any plans that might conflict. The good news is the platform is sort of self-selecting, meaning the type of owner willing to go to the trouble of using (and paying for) Rover (usually) has the type of well-trained and socialized pet you want to be around. If anything, the owners tend to lean overly cautious and indulgent and the pets lean clingy. I've never had a true behavior problem, though I have (of course) had to deal with the occasional bathroom accident.
I'd say the worst part has been the few times I felt uncomfortable with a dog or (more often) an owner during a meet and greet and had to say no to someone's face. Other than that, it's been a pretty nice gig for someone that likes dogs. The best part is how flexible it is (like Uber, Instacart, etc. you set your own schedule) and I'd say it's even better since you're doing the work at home and already feeding, walking, etc. your own dogs. There isn't much difference between 2 and 3 (or 4). It's also really easy to stop (or take breaks), so I would give it a shot and see how it works for you.