I do not know if you are committing the same mistake as Callum – one of my American friends. He once told me how much time he spends learning Spanish grammar and how he does not enjoy it, to say it cautiously.
Then he showed me his grammar book. I do not remember the exact title of this book, but it was something like “The complete Spanish grammar” or “Concise Spanish grammar”. Anyway, the table of contents told it all. There were chapters named like “Futuro perfecto” “Pluscuamperfecto” “Pretérito anterior”. If you are not familiar with grammatical terms or if you did not study Latin you would have trouble finding out what this book is all about. And definitely you wouldn’t get the feeling what all this grammar is for.
And the drills and exercises: sooo many gap fillings and correcting mistakes. No wonder Callum did not enjoy it, to put it delicately.
Generally, I am convinced that if you are using good software for your Spanish or a good texbook with audio materials, you do not need any other grammar textbook. Your course materials will introduce the grammar gently and gradually, while providing the relevant context.
However, if you still need a more structured approach or if you like to have a reference when you would like to go if you want to solve a particular grammar problem, I recommend you grammar textbooks that adopt a functional approach. That is, the chapters are organized around the aspects of a language, for example: expressing the past, expressing the future, etc. This is not only more comfortable and useful, but also gives you the sense of feeling of purpose: what all this grammar is for.
I remember when I learnt English as a second language, an invaluable help for me was “English in Use” by Raymond Murphy. The book met all the criteria I told you about.
But when I learnt Spanish, there were not many grammar textbooks available on Polish market, so I have always thought there must be some good Spanish grammar textbook somewhere else. Can you recommend one?