Just curious:
I know Euroleague is the biggest, but how does La Liga and whatever League Deni plays in for Maccabi compare?
Further, is Deni's production anything close to Doncic levels? Where would you rate him as an international prospect?
This article is a little out of date (in particular, I think European clubs have leached away some top D-League players, significantly weakening the D-League and modestly strengthening most international leagues), but still a good guide:
https://fansided.com/2015/11/06/deep-dives-measuring-level-of-competition-around-the-world/
Basically, Euroleague is the second-toughest league in the world, with the Spanish ACB pretty close behind. A significant notch below is the D-League, Eurocup (second-tier international behind Euroleague), major-conference NCAA basketball and top domestic leagues. This year we'll see Avdija and Maledon in Euroleague as well as in their respective domestic leagues (French, Israeli). We'll also see Killian Hayes in Eurocup and in the German domestic league. Finally, we'll see Ball and Hampton in the Australian domestic league.
Avdija is a significantly worse prospect than Doncic, and we can see that by the fact that he only tallied 51 total Euroleague minutes in his age 17-18 campaign. Doncic was far more advanced, playing about 700 minutes and starting several games in his age 17-18 season. Even if Deni makes a big leap, he won't reach the heights Doncic reached in his final Euro season (e.g. Euroleague MVP). That's not to say he isn't a top-10 pick, but there's no evidence that he's a generational superstar kind of prospect.
It'd hard to rank these guys right now because none of them have played a lot of minutes against serious competition. I think all of them have very real potential to go top-10 though.
I'll also mention Garuba again, even though he's a 2021 guy, since you ask about Doncic comparisons. He's obviously a different type of player, but like Doncic, he's starting for possibly the 31st-best basketball team in the world at 17 years old. That's rare, unprecedented before Doncic really. Unlike the 2019 international prospects, he's on a #1-pick kind of trajectory so far in his career.