God packs are 1:2000

5 cards per pack

Ignoring all cards received other than being pulled in normal packs

You should get a God pack within 10k cards on average

So open ~10x more packs and you should, on average, receive 1 God pack.

Someone having 20k cards and no God pack got unlucky twice but isn’t crazy at all.

To my knowledge there is no guarantee.

You could have 50k+ cards and not see one

Imagine rolling a 2000 sided dice and having to hit a 1

In 2000 rolls you should roll a 1 once

You could roll the dice 10,000 times and never hit a 1, that would be 50k cards.