I’ve got a mini goldendoodle who’s 17 lbs, he’s smart as a whip, very trainable and has quite a sniffer and set of ears on him, his eyes are something else as well.
We hiked Little Devils Tower trial in South Dakota last summer, the last 1/4 mile or so is essentially bouldering to get to the top and he did it with no help. I also have yet to find his quit button, anything we do with him, he always looks at us with a “what’s next?” look.
I’ve always said, I’d love to hunt him but I don’t have the drive to at the moment. With the popularity of blood tracking, I’ve thought about training him for that.
Regardless, based on what you described for what your looking for in a dog, mine (a mini goldendoodle) checks every one of your boxes.