Answer

Hello.
You’ve taken on quite a task. Very few professional philosophers have finished that book (I haven’t either). I’m not familiar with Yovel’s edition, only the one by Rothenstreich and Bergmann, and there it’s plainly impossible.
In general, I strongly recommend first reading about Kant’s thought and only then approaching the book itself. That will make things easier, and might even make it unnecessary. The important question here is: what is the added value of reading the original? If you’re specializing in Kant, then of course there’s great value in it. But if you’re interested in philosophy, and what matters to you is the arguments rather than exactly what Kant said and deciding between different interpretations, then in my opinion it’s less important. All of Kant’s books are important, but regarding all of them I’d say what I wrote above. There are shorter works like Groundwork for the Metaphysics of Morals that are easier. But my point applies to all his books.
In general, I don’t have recommendations, because it depends on each person’s taste and inclinations. I think articles in analytic philosophy are the most important material for developing philosophical skill. Classical works are more important for broadening knowledge than for improving skill.