[Designer] Using object to mask out objects below it, but still keep it visible

[Alchana]

I have an unpleasant conundrum. The selected diamond in the first image is on top of all of the others; I want everything else to not render underneath of it. I can easily achieve the desired look by simply setting the fill of the diamond to white (as in the second image), but this is not desirable as I want to export the final image with a transparent background, not white. I'm also able to achieve the desired effect by duplicating the diamond, putting the duplicate underneath the original, giving it a fill, and setting it to the Erase blend mode, but this makes working with it fiddly as I then have to deal with two objects at once. This felt to me like something that should be doable using booleans, but I've had no luck with those. Is there really no easier way to do this?

Edited July 26, 2021 by Alchana
Clarification

[firstdefence]

Which are you using?

[Alchana]

3 minutes ago, firstdefence said:

Which are you using?

Designer. Apologies, forgot to specify in original post.

[firstdefence]

I think you have found the least complicated solution in the latter technique, as clunky as that is. The only other option I can think of is adding nodes to the curves below and breaking at those points. 

You can always group the shapes and duplicate the group first and work on the duped group and turn off the original group as a kind of back up before adding nodes and breaking at those points.

Example sketch...

 

[Alfred]

If you want a diamond-shaped hole, make a diamond-shaped hole! Create a rectangle the same size as the canvas, put the diamond on top and do a Boolean ‘Subtract’:

Group the remaining shapes and position the group on top of the rectangle:

Clip the group to the rectangle so that the parts coinciding with the hole disappear:

If desired, remove the fills from the rectangle and the other objects: