You choose the perfect breed by figuring out your ideal energy level, exercise requirements, any specific temperament traits you are looking for (common examples: protective, easily trainable, easygoing/generally good with other dogs, etc), size preferences, grooming commitment, and considering the general "look" you like as well as any color/pattern preferences.
I always also advise considering what behavioral traits may be especially unnerving to you, or completely unacceptable, and to read between the lines in breed standard descriptions. For example, many breeds are supposed to be aloof towards strangers. In an appropriate temperament (confident, assertive), that can mean that the dog will occasionally test the waters as it grows up and decide "hey I think that person should go away" and say something about it (bark/growl). Part of raising that breed will involve expecting to have to address a dog inappropriately policing a stranger's movement/activity. In a dog with a less confident, more nervous temperament, that could mean a dog easily inclined towards reactivity to strangers.
From my research of rough collies, I place them in a similar category as Goldens, though more attached to specifically their people and with a more careful demeanor than an exuberant retriever- but a generally amiable dog, intrinsically motivated by handler praise and input, generally accepting of strange humans and dogs.
Whether a dog will protect you when it really comes down to it is a cr*pshoot, especially in a softer spoken breed like a Collie, and depends very much on the individual temperament traits of the dog in question. I'm sure there are plenty of Collies who would, and plenty who would not. As a breed, I wouldn't consider "stand and fight" as a highly selected response in that situation, but I also wouldn't consider any other response to be highly selected, either. Collies are a relatively large dog, and I have heard a lot of people report people being wary of their tricolor dogs (which are mostly black) vs other collies they've owned of similar temperaments but different colors.
IMO, a breed who has been selected more to protect is also going to come with other challenges you won't have with a Collie. Something like a Groendel or Teuveren (the black or fawn longhaired Belgian Shepherd coat varieties; separate breeds in the US but not in europe) is similar in looks and size and IMO more likely to be protective, but they're going to have higher energy requirements, are more reactive, and are less easy going about unknown humans and dogs.