An idea: write an anthology, with a different style/idea/angle for each chapter/arc/short, and ask readers the one they prefer. Personally I’d find a common thread between my ideas, make an overarching story distilled around for coherence, and then test each ideas individually in each chapter. Then check stats / feedback per chapter.
Might give you a taste of what’s working/appealing to readers. But again, like @joannekwan mentioned, the sample size might be very limited... you can mix both approaches, then asking in forum to vote for the chapter they preferred... basically like pilot nights on tv...
Edit: just saw your other post... so just forget 