I don’t think there’s a very clear answer. They’re the consensus top 2 in the league, similar age, career achievements and late bloomers. Both relatively injury free so far though Jokic is more available, both seem intent on staying all or most of their careers with their draft team.
Personally, I think it’s harder to build a team around Giannis you’re going to need people to compliment his weaknesses in shooting, free throws and late-game situations. Jokic dosen’t need as specific tailoring of teammates to his skills so your team might be more consistent through roster transitions. I guess you could knock Joker down for his defense but finding a power forward like Gordon who can cover up a bit on defense is easier than finding multiple good shooters.
Secondly, Joker’s game atleast appears like it’ll age better because it’s more IQ and finesse than athleticism. That might change if Giannis develops his game with age like Lebron did but it’s a less certain bet than Jokic.
You’re right, iso player is too broad of a term. He’s a great shooter and post player. He also collapses defenses when he gets the ball in the post, and is a great passer.
He’s not a great ball handler or dribbler and he’s not fast. He’s not a guy who I would expect to make things happen in transition. If I was starting a young team with rookies who like to run but aren’t that great off ball I think Giannis would be a better fit. The alternative would be dumping the ball into the post and ask jokic to score every play.