SwiftUI 2.0: Disable resizing of MacOS Sheets.

I am working with Xcode 12 beta 6 and MacOS 11 beta 5 and I have not found a way to lock the size of a sheet.

I have given it max, ideal and min sizes. I have tried to use fixedSize on the sheet and the children. Nothing seems to work.

This feels like a SwiftUI bug on MacOS. Which is beginning to feel like it is not ready for prime time on Mac.