@libstrong Yeah, our standard answer has been... get a DNA test to get a bit more certainty. But, who cares really. He is what he is. I love his doughnut bagel tail. He sounds like a fantastic doggie! Smart, affectionate, sticks with you on walks... sounds like an awesome little dude to me. Welcome to forum too!
Another possibility might be Rat Terrier. They do come in brindle, although that colour is out of favour. There is one in my neighbourhood that has a bit of a Basenji look to him, and his tail is very short.......not sure if it's natural or docked.