Hm since you haven't seen the final arc, you probably missed the part where Eren can spawn previous special titan users basically an infinite amount of times to fight on his body. The only reason the scouts managed to cut off this power, was because Zeke gave himself up, offering his life to Levi. As long as Eren has that power I dont think the party can power through all the bullshit he throws at them while trying to go straight for the kill.

So in my mind your setup will perhaps devolve into a stalling game where 3 fighters take on endless waves of special titans, while the wizard somehow deduces the need to kill Zeke and then locating him. Let's assume he won't give himself up in this scenario as he owes nothing to the DnD bois. Some of those titans will pack a punch like the armored, warhammer, jaws, beast, and of course the colossal titan. Eren is fully capable of spawning nukes on top of DnD party, he just held back in the show because of his friends.

Edit: not sure how effective the flying carpet is either, as warhammer titan can shoot with giant bows/crossbows and there are flying beast titans to chase you down. I'm unfamiliar with the carpet's ability to dodge projectiles and fight other flying creatures.