I applaud your idea. In my current position, I often feel like the “union rep” for the developers on my team and, despite not being a fan of most modern unions, sometimes wonder why we don’t have something similar for our profession.
I wonder, though, if GitHub couldn’t expand just a little and meet the desires you’ve expressed? Most of our code already exists there, as does or contribution graph. Add in a feature similar to CodeWars.com and you’ve expanded the ability to better verify your skills.
Best of luck, I look forward to seeing how you progress!