He’ll be a contender just based on his size, power and athleticism in the weak era that’s to come. Anything beyond that is conjecture.
Honestly I want to see him do well and i'd rather he fights bums and creampuffs like Tyson did when he was that young, to build experience and confidence, instead of trying to break the record. He has so much time. I'd spend the next 3-4 years crushing cans and build a foundation
Tua was definitely a harder hitter. Tua would've KO'd cold Mezentsev with first left hook. But I think Itauma is more versatile and quicker boxer than Tua
In the four-belt era, it would surprise me if (barring an awful injury or something) he never became a world champion. Beyond that who knows.