removing wall underneath door opening via door family

I have a custom door family that i created. My door family is working as i wanted, the only issue that i am facing is there is a wall underneath the finished floor level till slab level under the structural opening of my door. Visually there is nothing wrong, but if i create a section through my door, i see these unwanted walls. I tried to put a void or extending opening cut. but void affects nothing and unwanted wall stays, and if i modify the opening cut through the bottom, revit thinks this is my new finished floor level and my door floats on wall.

How can i achieve to remove the wall underneath the door opening.

Screenshot_1.png Screenshot_2.png
first image what i want – second image what i get

PS: I am attaching my door family but it is extremely complicated. This issue has nothing to do with this complexity. so please do not advise me to simplify my family. any custom door family put in a model with some thickness between finished floor level and slab level will work. I would attach the model, but it requires so many linked files and central model etc. I am also attaching a sample family that achieves what i want, but when i inspect and mimic what is going on in it, it is not working in my family.

Thank you in advance.

Attached Images

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  Screenshot_1.png
  (54.3 KB)
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  Screenshot_2.png
  (46.6 KB)

Attached Files

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  my custom family.rfa
  (1.75 MB)
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  sample family.rfa
  (1.63 MB)