Does anyone do user testing or short research calls? How do you keep it consistent and avoid no-shows?

I work full time in California, 9 to 6, and I want to build a small, repeatable side income that fits into my current routine (meal prep, gym, and not buying a bunch of extra stuff).

I can give 4 to 6 hours a week, ideally split across two weeknights (about 1.5 to 2 hours each) plus a short weekend block. I'm looking at user testing, product research interviews, and the short moderated or unmoderated sessions that pay per test. My goals are boring and specific: $250 to $500 a month, predictable, and not reliant on constantly refreshing apps.

Questions for people who do this regularly:

1. How do you keep your pipeline filled without spending more time applying than testing? Do you batch applications at a set time or use any tools to automate it?

2. No-shows and last minute cancellations: is that just part of the game, or are some platforms or study types noticeably more reliable?

3. What is a realistic acceptance rate once you are set up, and how long did it take you to reach consistent weekly earnings?

4. Any red flags that usually mean a study will be a time sink (long screeners, weird payment terms, vague scheduling, etc.)?

I don't mind being on camera and talking, but I don't want this to become a second job that eats my week. Would love practical tips on a sustainable system people actually use to keep earnings steady instead of random. Thanks!