Thanks for sharing your experience and glad to hear you've found a good job/team/product-environment!
My experience working with junior devs is that while they may be smart they haven't worked in teams and contributed to large codebases. So they may struggle to understand how a larger codebase is structured, where is the optimal place to fix an issue, how to structure their own code to be maintainable longer term etc. So code-reviews take longer, with seniors sometimes having to refactor a large amount.
I think some younger devs that contribute to open source projects do much better in this regard.
My experience working with junior devs is that while they may be smart they haven't worked in teams and contributed to large codebases. So they may struggle to understand how a larger codebase is structured, where is the optimal place to fix an issue, how to structure their own code to be maintainable longer term etc. So code-reviews take longer, with seniors sometimes having to refactor a large amount.
I think some younger devs that contribute to open source projects do much better in this regard.