Dante Exum
As far as guards go, the Utah Jazz alumni page doesn't have a lot to go through, at least not ones that don't turn the team upside down. Dante Exum can be the guy you need him to be this upcoming season. The Jazz need a pass-first, defensive-minded point guard and that's Dante Exum. He revived his career in the EuroLeague before coming back to the NBA as a member of the Dallas Mavericks and proving his worth. Sure, he's still not a great scorer but he can hold his own.
What he is now, however, is a good to great perimeter player on defense, and a strong enough shooter on offense that he won't hinder the team. He's also adding some size to the lineup should he return to the Jazz. He's taller than most of the guards on the team and more physical, which is a plus.
Pairing him with Kris Dunn would actually I've you a tandem that you can roll out against most teams, and then you can rotate him with Collin Sexton and Keyonte George, making sure that you always have a defensive-minded guard on the floor with them at all times. Considering how bad both George and Sexton were on defense, you're going to need at least two defensive guards to balance them out, so Exum and Dunn would be the perfect tag team for Sexton and George.