https://www.logos.com/product/41731/classic-studies-on-the-kingdom-of-god-and-kingdom-of-heaven
We had a similar problem with the studies on the life of paul collection, which was corrected, gratefully. Of course, you can't include every work on the kingdom, but it sure seems like Schweitzer should qualify for a classic studies bundle.
Schweitzer, Albert. The Mystery of the Kingdom of God: The Secret of Jesus’ Messiahship and Passion. Translated by W. Lowrie. London: Adam and Charles Black, 1914.
That's because this book (and Sweitzer's main book on the historical Jesus) is already created and included in this collection:https://www.logos.com/product/25855/classic-studies-on-the-historical-jesus
Hey look at that, I even own it! I should check my own library before making suggestions