Yeah, they do need that much exercise. Obviously it varies by individual, and mental stimulation is a lot of what they need.
They're prone to issues like anxiety, OCD, and even self mutilating or other destructive behaviors if not given proper stimulation. They are EXTREMELY intelligent, but not in the same way a lot of other breeds are. Their intensity and drive to work can easily turn into obsessiveness or be misdirected. I've known a few, with ill prepared owners, to become aggressive.
IMO border collies are not pet dogs. Sure, plenty of people who are not active in sports or living on a farm own them happily and successfully....but unless you're looking for a dog you can really actively train, take to classes, and CREATE outlets and opportunities for a dog that isn't a working/sport dog, you're not going to be a great home for a BC. I only really recommend them to people looking to compete in dog sports or have a super active lifestyle (IE horse people who will have the dog at the barn regularly, etc.)
That said, you can always fine a rare bench bred type dog that will tolerate more average exercise and mental stimulation. But I think if you're going to do that you might as well look at some other breeds.
Shedding I'd consider medium/high. They need regular brushing/coat maintenance and prepare to vacuum frequently. I don't believe they blow coat like some breeds. I could be wrong.
As far as mental stimulation you're going to be looking at things like agility, disc, fly ball, or really extensive trick training. There are other outlets like barn hunts, tribball, rally, etc. but that's going to depend on WHATS available in your area and how experiences a trainer you are.
I don't think I've ever recommended a BC to someone as a first dog.
That said, they're super smart, and I'm pretty sure the people who love them can't live without them. Not many other breeds can do everything a BC can with as much enthusiasm. They are VERY serious. Sometimes quite soft. Pretty biddable. Usually somewhat aloof with strangers.