No, exposure to the virus is like exposure to combat. You may not die, but the likelihood goes up the more time you spend exposed to it and the more of it you get exposed to. To keep with that metaphor a vaccine is like a war game, it won't kill you but it's not the real thing either. But if you've done it you're better off than if you hadn't.
This doesn't make sense. Do you have a source that says repeated exposure increases your odds of serious disease?
Repeated exposure increases your chances of disease not serious disease. Increased Viral load increases chances of serious disease. Apologies if that didn't come across clearly.