I’ve wanted to try post geese but have never really had a chance - everything I do is “prepackaged” and things like Wordpress or Confluence really don’t seem to care if it is MySQL or Postgres.
I learned a lot from a book from one of the core contributors to Postgres - https://theartofpostgresql.com/. It has actual real world examples with realistic datasets to experiment with.
I always seem to learn about the things that would have made my life easier after I've already done things the hard way.