What would you buy if you are only allowed to own three pistols?
NOTHING.
The question neither interests us, nor has meaning,,,,
And, I really dislike the way it is phrased....
First, I don't live under any authority that only
allows me 3 pistols, and if that were ever to change, for me, it wouldn't be a question of what to buy, but a (difficult) choice deciding which to keep.
Now, if
you are
choosing to only get three pistols, and you're a beginner, I would recommend getting a small bore (.22) a medium bore (.35-40) and a big bore (.41+).
I think at least one of them should be a revolver, and they all should have decent (or better) adjustable sights.
I'm not sure why you pick one for home defense, another for CCW and a third for range fun, there are many different guns that will easily do double duty and some that can fill all three roles adequately.
I am not personally familiar with the Walther you named, nor the specific CZ 75 model. The CZ 75 is a respected design, but all the ones I've been around have been duty class guns, not well suited to CCW. I am familiar with S&W L frame guns in general, and don't care for the way the full underlug models balance in my hands. Just a personal preference.
You asked for thoughts, so there you go, I'm an old grumpy guy still working on my first cup of coffee today
sorry if I came off a bit rude, but its one of my personal quirks, people saying "allowed" when it comes to our natural rights.
I have over a half century of personal experience with a number of handguns, revolvers, semis, and single shots ranging from .22LR to .45-70, and I much prefer older guns to newer designs, generally speaking.
If at all possible, get some hands on time with the guns you are considering. Handling them in a gunshop at a minimum, and if possible shooting them or something essentially similar. Go with what feels right in your hands, not what various "experts" say you "need".
My opinions are just that, and worth what you paid for them, possibly less
Welcome to handgunning, there can be a lot more to it than just self defense, if you're open to it, and I think it is quite an enjoyable hobby as well as having very important practical aspects.