I'm curious -- if you want a dog with the characteristics of a GSD, why not get one? Is there anything you do NOT like about the GSD?
ETA: There are "breed characteristics" but there are also the effects of early experiences which are extremely important in the formation of any individual's later characteristics & tendencies. Please google "imprinting" (the link below too briefly discusses some of these effects). The descriptions I give below of 2 dogs of the same breed are examples of how strongly those different early experiences twist and reshape the core's various genetic breed characteristics.
Imprinting (psychology) - Wikipedia, the free encyclopedia
I've had 2 AKC registered Labs, both females, both runts (their birth weights much less than their sibs), one from an AKC Lab bench line, one from an AKC Lab HT&FT line.
Bess we got (1967) when she was far too young (5 weeks old) and when we didn't know any better. Bess was never around other dogs until much later in her life and I'm convinced that her identity was with people--she never seemed to consider herself a dog (
never happily wanting to meet & greet another dog--as my present Lab, Puff, always does; that Bess reserved for people). While Bess was primarily devoted to my wife and me, she seemed to view herself as the facilitator to make
all humans feel well-loved and welcomed. As for security? -- any intruder who was allergic to dog saliva from being licked would be terrified of her.
Puff came into my life (2001) when I was single and after she'd spent her first 9 weeks with her puppy siblings. Because of my experience with Bess, I made sure that, during Puff's first year of life, she had at least 3 hour-long playdates each & every week with other puppies or dogs near her age so she'd have a proper canine self-identity. (That worked; she loves meeting & greeting other dogs.) BUT, I think also, because I'm now single and, during our first 5 years together, wasn't sharing our/my life space very much with anyone else, Puff is
extremely attached to
me and does NOT want to be separated from me. I don't think she'd bite anyone but, when she's with me, her barks sound very threatening at
any knock on our door, or
anyone who passes by as she supervises my mowing our lawn. The last 2 years, I've been very involved with a widow, B.; B. sometimes refers to Puff as "our daughter." Puff does like B. very much but still, obviously, does not want to be separated from
me. (Puff sometimes makes me feel uncomfortably like "her God.") Tonight B. and I were going to our usual Thursday night dance--leaving Puff at B.'s house, as usual the last couple years. Tonight, Puff did NOT want to be separated from us/me. She slipped out of the house, resisted my efforts for some time to corral her and put her back inside the house (although I'm sure she'd quite readily have hopped into the backseat of
my car.). She certainly seemed to NOT want to be separated from
me/us.
BUT I'm concerned about your concerns.
I VERY seriously doubt that a Labrador is the dog breed for you.
You haven't mentioned any awareness, or capabilities, of fulfilling a typical Lab's special needs, e.g.,
adequate amounts of exercise especially during their first two (maybe 6, 8?) years.
E.g., almost ALL Labs need daily vigorous exercise (e.g., running, swimming, fetching) for much of their lives. The generally accepted rule of thumb is 5 minutes for each month of life up to 1 year and then an hour after that. My Puff needed twice that amount/day to be comfortably docile and not chewing baseboards, computer wires, furniture, etc. So Puff got each dose about 12 hours apart.
IMO, Labs are special needs dogs.
For those who are comfortable fulfilling those special needs, the relationships that get formed are among the more/most satisfying that life offers us.
For those who are not, then those relationships will be miserable until divorced.