It seems to me your expectations are kinda reversed of what they should be. I'm not an expert but as a student myself, starting french as adult and now working towards C1, learning grammar feels like one of the most important parts of being able to truly comprehend the language. I've been learning for a total of almost 2 years, with a teacher, and I think every time I felt like I reached a plateau it was because I was letting my verb knowledge fall behind, or some other grammar component. Of course vocabulary is very important but most of the nuance in communication lies in the grammar at least on those levels. You can use simple, basic words but if you use wrong tenses you won't be able to communicate effectively. So it doesn't seem like you can progress to those levels without absorbing the grammar since they extensively make use of all that, I mean that's literally what those "levels" mean, that you have the capability to use all that grammar and have more depth and complex ability to express yourself. More on reddit.com

What you're looking for is called a reference grammar. An unabridged reference grammar can be a huge brick of a book that's like 800 pages or more, depending on how it is written. They're often written primarily for linguists, not just casual language learners, so it might be a difficult read if you haven't the background homework. More on reddit.com

My native language is Spanish too and being honest the french grammal is not easy for us eventhough we have lot of things in common so I recommend you use these websites which have helped me alot in terms of grammar: https://www.laits.utexas.edu/tex/gr/index.html and https://www.cliffsnotes.com/ More on reddit.com

Sneak up behind it and knock it unconscious with a baguette. More on reddit.com