Lemme try to make this simple. Get a hunting dog. The dog will naturally want to protect its "family." That's what they do. It may not attack an intruder--that's fine. All you really need it to do is sound the alarm and get in the intruder's face. Turns away all but the most serious agressors. And those, it'll at least slow down.
Individual dogs vary by personality. Some are naturally more paranoid than others. But most normal dogs learn pretty quick to understand who's "in the pack" and who's not.
Get a dog you'll enjoy. Most all hunting dogs will fit that bill. They'll do the protection thing by default.
When I got my dog (who is not a hunting dog, just a family dog), the thing I liked best is that I didn't feel the need to get up when things "go bump in the night." I learned pretty quick that, if it was anything to worry about, the dog would let me know. The only downside is, a neighbor cat in the yard is something she thinks I need to know about. But on those rare occasions when the neighbor teens came over to get one of my kids to sneak out, the dog made sure we knew something was up. That gave me confidence that NO ONE was going to get in, day or night, without facing the dog. And criminals do NOT want to face the dog.