I´m a Spanish native speaker and I am learning Swedish at a B2 level. The fact is that I feel that I´m stuck at this level and I do not feel any progress even if I study every day. I know that my Swedish is not perfect and I know I´m capable to master the language at a C2 level (I also want to master it to complete my studies in that country). When I speak to my friends in Swedish I feel that most of my expressions are too generic like if I an AI chatbot with no personality, and unable to acquire the slang words they use.
Any advices?

Someone shared an app or website that corrects your Swedish grammar and spelling.
It was fantastic, but I lost track of it and can’t remember how I accessed it.

Thank you!

PS Bonus question, I just bought the Rivstart A1/A2 books. I saw a couple of SFI YouTubers use them, do you have a favourite channel?