Server Rack Temperature Controller Bracket. Uses standard rack hardware, and the controller below.

I'm a fan of textured sheet on PETG for finishing, but you can print on anything. No supports needed.

You will need a couple #4 screws (1/2") to join the halves.

Controller: https://www.ebay.com/itm/303495907809

Rack: https://sysracks.com/catalog/sysracks-srw-600-g/12u-24-depth-24-x24-x24-5-wall-mount-19-enclosure-sysracks-srw-12-600-g/