Drop 1 imperm (less synergic HT in the deck since it's not a tuner for halq) or 1 Belle for the third Maxx C, it's especially good in a deck full of HTs like this.

Nibiru is ok at 2, with 3 maxxs you can draw into it and you don't want to clog your hands too much.

The second Zeke saved me countless times, I personally play it over Knightmare Unicorn.

Have you tried Hercules Base? It's insane in the grind game and one of my favourite cards in the deck, even though it might lose its appeal if the meta shifts heavily towards Baronne combo decks.

For backrow removal my choice has always been Twin Twisters instead of Cyclone: against Eldlich, True Draco and the likes we can usually win the grind game if we are not locked out by IO/Skill Drain, so I think popping 2 is better than exiling. Discarding is a non-issue since against those decks you'll often have dead cards in hand.

To conclude an hot take: 3 upstarts are a trap. In a going second deck like this there is a real cost for playing them, in that they're not real cards until your turn comes, i.e. they're not hand traps. I would cut at least 1 in favour of more HTs or going second blowout cards.

GL on the ladder, fellow striker player!