Yeah, we know...Luis Scola!
Well, you're aiming high here if taking comparison with Sabonis as underappreciation. It's your choice though, it's not impossible, and he's gonna be great player, already very good, but my projection would be something between Sabonis' impact (in different ways a little but, but generally the same impact) and something between Sabonis and Jokic impact (optimistic projection).
Sengun is not going to be as good as Jokic. Jokic is more special in skill, in size, in toughness, in natural flow. Jokic, IMO, won't be matched.
Now, with Sabonis the comparison is much more interesting. Sengun has smoother skillset, like plasticity, both post and face to the basket offense. Softer touch. Sengun may be fancier and maybe even more gifted to the degree passer, but he doesn't have Sabonis' natural "under the flow" facilitation game. Sengun is not as quick and natural facilitator as Sabonis when he is in the middle, and Sengun takes his time (Jokic has both - Sengun's nifty/fancy passes and natural flow quick distribution even without thinking). So it's hard to say who will be better passer. But when you build around point center, Sabonis is more more natural distributor. Those hand-offs, those quick-outs, those multiple tough screens in very short time, short roles.
Sengun isn't as shifty and agile as Sabonis when it comes to screening.
Both Sabonis and Sengun can't shoot. Sengun's solid three point shooting is a complete asking ATM. He can't shoot and I doubt he will. Some shots goes like way off, like air balls.
Sabonis has higher motor, even if Sengun has also high one, but Sabonis is unmatched, he's like a robot and he plays hard in each and every possession. He can out-run and out work, out-hustle (and he does) any big man in the league. Sengun has a bit of Jokic "gifted laziness" in him. Thus, Sabonis is playing more physical game and more consistent with the effort. There's no surprise he leads the league in double-doubles and rebounds.
Sabonis is a better rebounder.
Sengan has midrange scoring game, at least better one, cause Sabonis in NBA shoots jimmies too. But Sengun has craftier finishing game, including mid range all sort of shots.
Defensively...Maybe Sengun will be more flexible, but won't be as tough most likely and likely won't be better rebounder. Besides, I think in open space in perimeter, Sabonis has better feet work in isolation defense. Nevertheless, Sengun may be more flexible shot blocker, better reading defensive situation. So it's really hard to make any conclusions yet. Both sort of unreliable defenders generally.
Oh, and Sabonis is quicker and more natural with the ball in transition offense...Even if Sengun can do it too, but Sabonis is better at it.
Time will tell.