Deutsche Soldaten was recommended to me two years ago when I asked a very similar question. It is out of print and expensive, even for used copies.
Instead, I purchased German Infantryman Operations Manual: The German soldier 1939-45 (all models) (Haynes Manuals). It is muddled, poorly written, and did not answer most of my questions.
After reading the previous book, I accidentally discovered German Combat Equipment 1939-45 (Men at Arms Series, 234) (Men-at-Arms, 234) from Osprey Publishing on my book shelf. Apparently, I was interested in this subject 20 years ago! This cheap, short, little book, only 48 pages, is far more useful than the previous one.
I am currently considering purchasing Fighting Men of World War II Axis Forces: Uniforms, Equipment & Weapons. At 384 pages it is more comprehensive than the previous two books
World War II German ground vehicles is a very broad subject. Not only did the Germans utilize domestic vehicles, they impressed into service a wide variety of captured equipment. The topic is so expansive, no one book comes close to covering all of it. Books that try mostly offer a small picture or two of each vehicle, followed by a rather short descriptive paragraph.
In my opinion, in 2024, the Wikipedia is a much better starting point for German vehicle acclimation. Beginning with a page such as German tanks in World War II, start reading and follow the links. The information thus provided will provide a better foundation than any single book on the same subject.
Once you decide to focus on a specific unit or vehicle, that is the time to seek out a definitive book and begin building a research library.
My method of research may not work for you. While vehicle articles in the Wikipedia are usually pretty good, bias and errors are common. I definitely understand the satisfaction of a good book.
The Complete Guide to German Armored Vehicles: Panzers, Jagdpanzers, Assault Guns, Antiaircraft, Self-Propelled Artillery, Armored Wheeled and Semi-Tracked Vehicles, and More is still in print. I do not own the book but it gets mostly good reviews and has the virtue of being available.