What do junior/intermediate backend developers do?

Im front-end leaning dev but Im trying to pick up more backend tickets to expand my backend skills. I am wondering, what are the responsibilities? Id like to bring it up to my manager and push similar iniatives as well. So far I have done : - Done database migration by creating new tables or add/modify columns - Create and adjust endpoints, so that the client can say update a new column in the database with new API ver