Junior talent becomes senior talent by virtue of acquiring experience. Doing the wrong things and learning is one way of acquiring experience, but being directed by a mentor is a much more efficient and productive way of acquiring that seniority. A lot of lessons learned from reinventing wheels can be distilled down into a conversation or a pair programming session, but in the absence of senior leadership, it becomes a week long hacking session on a library that will ultimately rot in Git forever because it's foundationally unsound.