The blurred background / frosted glass effect on the new One UI 7 widgets look fantastic. Do you think Samsung has an API that allows us to use the same effect for third-party widgets? I would love to create similar widgets with that appealing effect.
Yeah, it looks beautiful.
Hopefully Samsung will consider it for 3rd party if possible. 
I am not sure whether it is possible or not currently, but you can check here for details.