See whether anyone complains about the problem you picked, without asking a single leading question.
These posts were written for peers, not in answer to your survey. People say what actually bothers them.
If ten communities turn up nothing on your problem, that is worth knowing this week instead of next year.
Accept the posts that match, leave notes on each one, and export the set when you need to show your work.
“Every newsletter felt essential when I subscribed. Now my inbox is unusable.”
“Brands keep asking for my UGC rates and I'm making the numbers up.”
“I've shipped four side projects this year and every one died at zero users.”