Launched with $200 spend. How to increase first posts?

I built a site using no-code Bubble.io. It's basically ProductHunt for pharmacist projects.

I launched on Twitter with a $200 ad spend over three days. 20K impressions. 300 engagements (1.6%). 46 link clicks ($4.30/link).

Now imagine ProductHunt with no products. Instant bounce right?
Yes, per the analytics most people clicked the one post then refreshed then bounced.
That's where I'm at. Chicken and egg. I need some initial content.

Learnings for the next iteration

• Engage directly with warm leads, all the pharmacists I know, through every channel to ask a personal favor.
• Move the Post button from the second screen to prominence.
• ?Add a walkthrough bubble to introduce the post button.

Any tips for driving these first posts?
How good is 1.6% engagement on a Twitter ad?
Any tips or hacks I need to know about?
What would you make sure to do next?

Current MRR = $0 (July 24, 2020)