[Update: The original had lots of extra vertices for some unknown reason. I recreated the object from scratch to remove them.
.blend file and images updated.]
I'm trying to create a UV map, and it always ends up warped.
Are multiple independent seams allowed? If so, I'm at wits' end.
I tried creating the object a number of different ways. This particular one was created from a cube, moved z face, extrude x face, extrude y face, limited disolve, inset z face, extrude inset z face.
(I can always condense that by splitting it into two and flipping and rotating one of them.)