Ferocitus
Deity
I have a constant crash on turn 889. It happens during AI turn. So it is a bit of a record I guess.
Civ 6 + all DLC and patches. Giant Earth with all nations.
Terra (Giant Earth, enormous size, no Barbs) is very stable for me with 16 civs and 24 CS.
What is the most civs+CS where it hasn't crashed for you?
(I'll try cranking up the number of civs myself as well to push it to the limits.)