Use the 3MF file and try to only adjust the printer type and layer height–it's been optimized for 0.2mm layers on a 0.6mm nozzle, and prints beautifully. Use 4 perimeters and 100% infill so the long part is just perimeters. You might slow the print down and increase cooling on that part for better finish.
Attach with 3M Command Strip Medium size, cut to fit, and optionally add a single screw to secure it further. Print in PETG or stronger given the stresses on the joint. There's just enough clearance for all inputs on all corners.
Feel free to remix with OnShape: https://cad.onshape.com/documents/1e34ba1e3955391953244d09/w/7a705cec00b0e66f57893d86/e/d5c486a1b65851ccf2192b65?renderMode=0&uiState=63cf05039a3cc339da331bbf
The author marked this model as their own original creation.