prediction for final duel
Yusaku will face off against Ignis, who takes on the form of his alter-ego, Playmaker.
We just got started on the series, so it's way too early to be predicting this.
But by the time we get to the final in a few years, Yusaku should've either gotten his grudge with Hanoi over a long time ago and actually enjoys dueling, or he still remains a person who only duels for revenge (and cue Yugioh equivalent of another anime character; hopefully he has changed by then).
That, and Link Summoning and monsters should be far more sophisticated than they are at present, and we can see a full array of plays made.
Not trying to push your idea down, but the story is still being fleshed out; considering it's about 3 months old and hasn't gotten very far. How long they'll run VRAINS for; idk, maybe the usual 3-4 years or shorter depending on how things go.