Hi @Anonymous,
Rather than try to edit your geometry, I started from scratch.
First I drew the outline for the base and offset in 5/8" to create the inner wall.
I then presspulled to a height matching the height of your object.
Next I used the outer outline and prespulled that to a thickness of 5/8" to create the "floor" of the object.
Next, Using sections, I grabbed the profile of the curved edge at the top of the box.
I swept this profile around the outer outline. This I exploded but retained the upper and innermost line at the top.
Next, I lofted between this retained inner outline and the outer outline.
Next I presspulled the inner outline so I could subtract it from the lofted solid.
Then I moved each place into position and used UNION to make a single solid.

I have not done the top because I am not sure what your design intent is as the shape does not match the shape of the box.
I went back in and created a closed pline profile for the lid. I then swept this along the outline at the top to create my solid lid. This is a nice, easy way to create the solid lid.

Perhaps this is enough to get you started. I have attached my version of your drawing so you can examine each of the steps.
Please select the Accept as Solution button if my post solves your issue or answers your question.
John Vellek
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