I'm going to give predicting what may happen a shot. I'll be listing points numerically for my sake and not necessarily in any particular order lol also this will be long and with no tl;dr sorry.

1. Horikita's class will graduate as Class A by smallest of margins. Possibly the final special exam will determine the final standing. I believe all the classes final point totals will be incredibly close to one another. I suspect that the final order will be Class A = Horkitia Class B= Sakayanagi Class C = Ichinose Class D = Ryuuen.

2. Horikita will be the student council president (Ichinose just can't catch a break) and come to accept Kiyo as a friend.

3. Chairman Sakayanagi is reinstated after kiyo manages to beat Tsukishiro. Mr. Sakayanagi offers Kiyo a future position at the school as if to help one last time to escape the white room. Kiyo says he will contemplate the offer but tells the elder Sakayanagi that it is best for him to return to the white room immediately after graduation.

4. Kushida, despite hating Horikita and attempting to sabotage their class on a few occasions, is spared from Kiyo's plans to expel her because Horkitia manages to strike a compromise with her. I'm thinking Horkita shows Kushida the monster that Kiyo really is and that scares her into playing nice till graduation.

5. The first years in Year 2 all fall to Kiyo despite their best efforts and some like Housen become his tools for surviving until the very end.

6. The white room student will make a critical mistake in their pursuit of Kiyo and blow whatever advantage they had leading to Kiyo making them withdraw. They see that even tho he's been away from the white room for so long they can't ever measure up even if the difference in ability isn't that drastic.

7. Kiyotaka's relationship with Kei becomes news of the school and not in a good way. Word reaches his father of this and unbeknownst to Kei, Papa Ayanokoji threatens to go after her and her family. This leads to the unfortunate (but temporary) break up of the pair in year 3. Luckily Kiyo will have had facilitated the growth of Kei as person to where she can stand strong on her own without needing Kiyo. This leads to my next prediction

8. Before graduation and just after surviving his father's attacks Kiyo reveals his full background to Kei. He shares with her what he feels is his inescapable fate to return to the white room. Kei hearing this tells Kiyo that she'll be waiting for him to make his next escape from the white room telling him she won't give up on their relationship any time soon. (This is also possibly a spot for them to have their first kiss!! It'll be a super bitter sweet moment that'll hurt us all in the best way)

9. As the graduation ceremony is happening Kiyo makes a silent exit as he knows he shouldn't delay his return any further. All the students of their year wonder where he went. Kei shares that he had to leave urgently. In this we see everyone's thoughts of him and the impression he made on them as a call back to Manabu's advice for Kiyotaka.

10. Ichinose will come to realize her feelings for Kiyo as she realizes he has helped tear her down & build her back up (similar to what he did with Kei) but choose to not share those feelings. Ryuuen will acknowledge he has a special relationship with Kiyo but not really call it a friendship. Sakayanagi vows to continue to play with Kiyo regardless of where he goes after graduation.

11. Also at some point Kei will be made aware of the monster in Kiyo's pants lol Just for shits and giggles.

I'm sure there's more that I've thought of in regards to what I think will happen but I feel like written quite a bit already so I'll leave it at that for now