Everything about a dachshund crate is about the spine
Miniature dachshunds are chondrodysplastic — their legs are genetically shortened while the spine is normal length, which means the disc-to-vertebra ratio in their back is under mechanical stress from day one. Roughly one in four dachshunds will experience intervertebral disc disease (IVDD) in their lifetime, and the trigger is almost always small repeated impacts: jumping off couches, jumping out of crates, jumping down stairs.
The crate itself should be low-profile — an 18" or 22" wire crate placed on the floor, not on a bench or in a stack. If the crate sits at any height, put a soft-carpeted ramp at the door. Do not use elevated crates with a step-down of more than a couple of inches.
Inside the crate: a firm orthopedic pad, not a plush pillow the dog has to climb up onto. The goal is a flat surface at floor level so the dog can walk in, turn around, and lie down without any vertical movement.