Pick a community you understand and read what it is already fed up with.
You describe an audience. Probelet picks the subreddits where that audience talks about its own work, then reads the recent posts.
Each one comes back as a plain sentence, the words the person used, and a link to the post they wrote.
Complaints are tagged by type, so manual work, broken workflows and missing features separate themselves.
“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.”