Warning: Received `false` for a non-boolean attribute. How do I pass a boolean for a custom boolean attribute?

Try this instead:

comingsoon={value ? 1 : 0}

As of 5.1 you can now use transient props which prevents the props being passed to the DOM element.

const Comp = styled.div`
  color: ${props =>
    props.$draggable || 'black'};
`;

render(
  <Comp $draggable="red" draggable="true">
    Drag me!
  </Comp>
);

You have to add $ prefix to attribute:

$comingsoon={value}

Styled Components had added transient props in 5.1 version: https://styled-components.com/docs/api#transient-props