IKEA Besta cabinet is crooked - What can be done?

My opinion: Look at the gap in the middle. The carcass is not crooked. You just need to align the door correctly.

by which the top door rests on the drawer front.

The doors must be aligned by turning the hinge screws.
However, the instruction manual is included with every door!

Push the wardrobe to another spot, it must be straight there. It’s probably just the floor that has some unevenness.

He definitely has a nailed back panel, was it nailed at a right angle?

Thank you for the answers. Effectively, my floor is much more uneven than previously assumed. The closet is now definitely standing straight, aligning the door was still a challenge, it is probably really warped or at least too heavy for the hinges. Oh well.

Aligning the door was still fun, it is probably really warped or at least too heavy for the hinges. Oh well.

I have the same ones. It can be perfectly aligned, even if it's tedious at first.