There’s a Discover Dogs at Crufts every year, as well as the one in London.
From your description of what you’re looking for, you want a well rounded, take anywhere family pet, but prefer large breeds.
I wouldn’t have a Dobie, for all the reasons others have stated, plus the heartbreaks that are Wobblers and DCM.
I had the most wonderful GSD in the late 80’s/early 90’s. She was a big, long-coated bear and came to us when we found her half-dead under a bush. She was my first ever dog, we nursed her back to health and she was loyal, loving, obedient and didn’t have an ounce of aggression in her. When we lost her at around 14 years old we looked into getting another, but even back then, were advised that it would be nigh on impossible to find another like her. Both conformation and temperament had been ruined through overbreeding from poor lines. There were still a couple of ‘old lines’ around at the time, but they were incredibly difficult to get a pup from. Also, public perception of GSDs had really declined by then, so taking them everywhere with you (as we did with our old girl) had become harder and harder - I think that perception is even worse these days.
If you are looking for a big-ish family pet you can take anywhere and train fairly easily (obviously with the necessary input and effort) as others have said, I would look towards gundog breeds, possibly show rather than working lines. They tend to be biddable, soft mouthed and trainable and public perception of them is better, which makes it easier to take them everywhere.
I do think if you are unsure, a trip to Discover Dogs would really help. I did this when I really wasn’t sure what breed to go for and ended up with a breed I’d never heard of, but was perfect for us.