How to manage external beta tester feedback

Right now we are using a WhatsApp group for feedback, and then someone uploads it into a Google Sheet.

Are there any products where we can define all the tests for the testers to run through, and they can give feedback on that test? If all is good, they should be able to mark it as so. If there are issues, they should be able to leave a comment about what the problem is and upload a screenshot.

This should end up in a dashboard where we can analyze this data.

I am looking for something simple. I've tried Google Forms, however, defining a test with a comment field is just so clunky.

Bonus

What I really want is something where I can define flows through the app with a flowchart, and that can be broken down into individual tests for users. (For example, there can be several ways to get to the login screen. I want to define all the ways in a flow chart.)