How do you get the first feedback?

Hey,

I just launched https://www.stemin10.xyz/ a tool to help me learn science on the toilet.

Mission:
Get feedback for the product.

Approach so far:
Cold message 50 people on LinkedIn

Yielded:
5 replies ✉️
3 visited the site 🎉
2 gave feedback ☘️

Posted on twitter to 35 followers

Yielded:
Nothing

How do you get your first couple of testers?