Let us say the Titans are a thing.

[Stealth Green]

Why would they be OK with the stuff Kronika did and no one tried to stop her.

What if 1 of the 3 other elder gods Kronika killed were their childs or where are th see 3 from?

 

[HeavyNorse]

Maybe it was out of their control, as she is a Titan as well and controls freaking time.
Maybe they didn't know or didn't care.
Maybe whatever she did wouldn't really affect them.
Maybe she killed them, imprisoned them or otherwise prevented them from intervening.
Maybe they fear her and didn't dare to go against her.
Maybe they just weren't important to the story of MK11, so NRS didn't feel the need to show us more about them.