How would you explain the cosmere simply?

[Coinshot Courier he/him]

Whenever I try to explain the cosmere simply, I can't really. It's just too complicated. So how would you guys?

[Quantus he/him]

It's a shared universe, kinda like the MCU.  Each series is set on a different planet by and large and has it's own story and magic systems and things, but there are worldhopping character cameo's and shared aspects of the different magics and things like that.  

I could go on (and on and on and on) but I think that's the elevator speech I'd use.

[Lego Mistborn he/him]

Quantus is right. Be abstract and it's easier.

The only thing you could add is there is a dead god that lives on in 16 fractions of itself, each embodying different traits. No need to go into specifics of the shattering either.