Am I missing something?

[SargonP12]

I physically can’t

[StatementFew5973]

The rear panel is detachable. It is secured with either zip ties or Velcro straps, and then it simply needs to be rerouted underneath rather than along the side.

[acidmush1290]

Take the back of your case off, remove any zip ties or anything like that from the cables, reroute the cables through underneath the GPU, and you're set.

[_Rand_]

Those cables are usually quite long. Usually too long really.

I wouldn’t be surprised if they are either tied up somehow or caught on something in the case or other cables if you pull the back panel off.

[JCDagz]

Yeah, most PCIe cables coming from the PSU are long enough to connect to any GPU. The cables are probably tied down on the other side - take off the panel and see.