Conformation should not really be that subjective, don't you think?
Not sure I understand what you mean. There is a standard that the dogs should be of a certain size, with a certain look to their head and body and their temperament should be of a certain character. In real life they can be identified as a Doberman if you saw one a city block away, even if it had natural tails & ears, it is unmistakably a Dobeman. However, if you were to take that same dog to a show, the judges might not give it a 2nd glance, and for that matter you may do the same. Too small you say, or too pointy of a nose or the eyes too round and doe-like, rather than a fierce stare. That is subjective to your opinion, even though the dog may fall into the standard as written. The Blue dog you mention is not in FCI standard. They don't accept Blue of Fawns. So right there you had a perfectly wonderful dog, that wouldn't be acceptable at all by some, but is acceptable by AKC.
The idea that some focus on looks and others on function seems a bit half ass to me.
Some people like ice skating and others like football. Some Doberman breeders concentrate on breeding a certain look to present in the show ring and they never consider any sports because "it took too much time to train". I mentioned Fast Cat because you didn't even have to train, just turn them loose to chase the lure. They declared it too dangerous and didn't want to take a chance. So that's a far end of that spectrum, but it's out there. The other end is those mentioned in this very thread that breed mainly for a working athlete. Yes they care about looks, but if you have an IGP3 dog bred in America that qualifies for FCI World CH but is disallowed because it's been cropped & docked - So now many working line breeders leave their dogs natural. That won't fly in the American show ring at all. I believe it's allowed, but your could probably count on one hand how many have reached CH level in the last 50 years in AKC with ears & tails intact. The other thing is when they are breeding the very best working lines and they have the exact temperament they've worked for years to get right, and is still sound doing extreme sports and still trialing at age 9, they have little to no interest in getting a beauty queen look by crossing over into the show dogs with zero sports titles. Chances are they would produce puppies that could work a little but not to top level and be too plain to please the judges in the show ring. And be a handful for a companion house dog.
There are many breeders who have dogs that can and do both, they just aren't common. Like I said earlier, if you know in your mind what you want, just start looking and you will find it.
So we have 2 - 4 distinct lines -
-American show lines which in todays world, the highest ranking CH's have several lines of South American in them.
-Euro show lines, which I'm not familiar with as far as winning looks but there are at least a dozen well known names/lines that heavily carry early DCM, Some will show IGP1's and claim they are good protection dogs, but they are rarely tested to the top levels.
-American & European working lines - dogs that are proven in almost every generation to IGP3 levels, I include American and Euro working lines as one because almost all working lines bred in America go to primarily Western Euro working lines . Yes, they are generally smaller and "wirey" not stocky and blocky - but they have good bone and distinct muscling.
-BYBs - these are breeders who mainly produce large numbers of puppies with no distinct purpose other than selling puppies. They will not have sufficient health tests, some claiming clear of heart disease because DNA tested "clear" or "negative" (this is a RED flag), they won't have proof of hip & elbow reports etc etc but they will always have a litter on the way. Some of these puppies will turn out to be perfectly good pets with no problems and some will be a financial and emotional disaster. Almost every dog in a shelter comes from BYBs because the breeder abandons the buyer after the puppy is sold.
With your interest in doing some bite sports for fun & learning, you should go to UDC and explore their website - the members there strive for the Total Doberman which meets the standards of show & working & correct temperaments.
https://uniteddobermanclub.com/about-udc/purpose/ They also require a temperament test to be passed before awarding their physical show placings at UDC shows, which is something I consider extremely important to this breed.
Hope this helps!