Stop arguing about slots for Champions. Seriously. The best way to do it is something like Siege, where all points standings are combined and points are heavily dependant on international performance. This means, better regions + teams = more qualification for better teams. But wait you say, wouldn't that mean an exclusive NA + EMEA + some KR event? No, there are still regional qualifiers, and you can still earn points through top placements in your region. Here's the link:
https://liquipedia.net/rainbowsix/Six_Invitational/2022/Global_Standings