How you find founders who hire freelancers?

We are developing the product related to the business owners/founders who hire freelancers, especially in the tech domain.

How I find the early users?

Currently searching here-

1. Linkedin- Searching the keywords "freelancer" and finding the post and their owner and then contacting them.
2. Twitter- Searching the keywords "freelancer" and figuring out the founders who are looking for freelancers.
3. Reddit- Following subreddit like /entrepreneur, /EntrepreneurRideAlong, /freelance, /Freelancers, /Entrepreneurs, etc, and engaging with the post owner if I find suitable.

What else you can suggest? I am not able to find many founders here.