Catalonia (the autonomous community or "nation" which Barcelona is the capital of) absolutely does have:
- its own parliament: https://en.wikipedia.org/wiki/Parliament_of_Catalonia
- its own legal system, in the sense of laws passed by the aforementioned parliament
- its own justice system: https://en.wikipedia.org/wiki/High_Court_of_Justice_of_Catalonia
- its own education system, nothing special about that, even in Germany each state has its own education system
- I can't easily find information on taxation, benefits, or housing, but strongly suspects those are regional matters in Catalonia too
Nothing I wrote is about "denigrating" people wishing for self-determination, or about "supporting the oppressive larger states". It's just currently a fact of the world that the independence movements in those places have not yet been successful. They might still be in the future!