this is moreso an observation I made while googling around and I don’t really have a reason but here’s what an article had to say:

Interestingly, large felines like tigers and lions do not have slit-shaped pupils but round-shaped. The reason for this is not exactly defined, but it is thought to be due to their greater height off the ground, their behavior as active foragers rather than ambush predators, or differences in their circadian rhythms compared to cats.
https://www.catster.com/lifestyle/why-do-cats-have-slit-pupils/