i think a straightforward "ivan lets till win" storyline for their zomst round would 1) have too much overlap with sua and mizi and 2) wouldn't track as much with ivan's motivations in canon like. this was basically the darkest most morbid take of sua's desires from canon: mizi is permanently blind to the realities of the world around her and sua can exist in a perpetual cycle of shielding her from further harm by letting mizi win and she can watch mizi and perform on stage with her forever! (at least until she has nothing more they can take) that's a happy end for her!
but for ivan, since they're already undead and winning doesn't mean "living" in the same way anymore, i don't feel like he'd do the same thing bc all it would accomplish is perpetuating a cycle where till is still made to perform as a spectacle against his will with no end so i think his actions would lean more toward trying to free him in some way rather than just take losses for him?