That seems self-selected and biased toward their own experiences. When I was a junior I was allowed and given free reign to design the test system for the prod

That seems self-selected and biased toward their own experiences. When I was a junior I was allowed and given free reign to design the test system for the product and implement a design system for the frontend team. Junior doesn't mean stupid, it just means less experience. How else do you expect people to gain experience if you don't give them basic independent projects?