Nah, he's faster and more mobile than Jankunas. He also has more explosive face to face game and can put the ball on the floor, while Jankunas is traditional PF. Tubelis 206cm already. I think he's more of a center in a long run. I disagree with you. He may not be drafted, but not because of lack of shooting, but because of limited upside if someone would decide that. The key for contemporary bigs is to be able to step out and switch, Tubelis can do that. Shooting is highly required, but not more than some ability to put the ball on the floor, pass the ball, to have good IQ and so on. Tubelis has the package to be drafted, IMO.
PS: Drafted, doesn't mean to make a career in the NBA. We have Reinaldas Seibutis and Gudaitis drafted, but, IMO, both won't ever play in the NBA.