Well, I finally got some answers!
I finally got answer as to why DbD will (probably) not have Crossprogression for Xbox and Ps4 (I asked Microsoft but I think it applies for Sony too?)
There you go, it's BHVR's side who doesn't want! ^^
Should've hid my name, oh well 😪

Comments
They said in the latest Q&A that they're considering it and how it would work.
Mind linking it, I was at school and couldn't watch it
well I hope ps4 gets it.
I'm gonna be honest, I'm betting they wait until the new console comes out so they can link to it instead and save a lot of headaches.
could happen. the PS5 is going to have backward comparability with PS4 so no worries there.
it's one of the top topics on discussions
It was leaked that cross progression will only be with PC/Stadia/Nintendo switch, sorry console users better hope these leaks are scuffed.
they wouldn't do it for 2 consoles they'd want to do it for all of them or not at all. that would be the smart thing, plus Stadia is dead