Thanks very much for your assistance. If I could, I would simplify the sentence. But according to my instructions, it should not deviate from the original too much. I appreciate the help you provided while taking into regard the specifications I had mentioned. Very best.
The original sentence is best. It's perfectly fine in every way. It's not the easiest sentence to read, but that fits with the subject matter (they, shrewd and ruthless, were not easy to deal with) and should not be changed. The sentence was deliberately written this way.