I've tried lots of German text books, and 99% of them are essentially very easy grammar tests, which you quickly learn to fill, without actually learning to speak. In Goethe Institut's courses you also simply fill many tests, but in a group. This may help preparing for an exam, but not to learn anything.
That said, I'd love to see excercises on a really hard matter: verb controlling the noun. E.g. ich vermeide <which prep?> <noun|infinitive>. And not just random verb + random object, but sequences of the same verb, to get it remembered.
I find the 'Deutschkurse Passau" workbooks [0] to be the best at focusing on grammar structure and providing useful practice. They can be worked through without an instructor (provided you've had some exposure to the grammar at each level.)
0. https://www.deutschkurse-passau.de/JM/index.php/downloads
My main complaint with most of the other German language coursebooks is the grammar lessons are too scattered, and the main effort in doing the exercises is figuring out what they want you to do.