How to toggle crossplay in Call of Duty: Modern Warfare

So I just got warzone, and I need to create an Activision account, as this is the first time it's required. I try to enter in my information, but it says invalid

Call of Duty Warzone 2.0 - How to See Your Activision ID

I'm trying to make an activision account and it keeps saying invalid user. But doesn't ask for a username. Solution? : r/Warzone

How to make your Activision account data publicly available

My Activision account was hacked

How to Change Your Name In Warzone 2

So Activision allowed my account to be hacked, what's next? : r/modernwarfare

Understanding How Long an Activision Account is Under Review

Activision Denies Reports That 500,000 Call Of Duty Accounts Have Been Hacked

500,000 Activision accounts have been leaked