Honestly, you don't need to "learn" or "understand" much grammar explicitly. I think it definitely helps get you off your feet, as you can "decode" sentences if you remember grammar rules, but eventually the grammar has to be internalized anyway. This happens when you are repeatedly exposed to the same patterns in context. I don't know how English or Norwegian grammar works, and I'm fluent in those. I skipped grammar in Japanese and focused on reading, yet I can understand most things and I can tell when something sounds wrong.
Clearly you and I learn differently. If I need to apply suffixes correctly, I want to understand how to do it predictably without learning every single form for every single word. Even if patterns coalesce in my mind into an intuition later, I appreciate seeing the shape of these patterns. Especially when they’re so elegant. Why is sharing that a problem?