If you have a substantial community, it's just a matter of sharing the same content (depending on the social media platform) with a different approach and see what they react to.

You shouldn't focus that much on research but to see what get people to convert into users or clients.

The reality of a startup is that most of the cases, you can't do exhaustive research, and what people consider as proof-of-concept is always going to be sales/conversions.