Shelf to hold a Google Fiber GFRG300 Router (or anything else you want).

Printer: I printed using a Bambu Labs X1C with AMS.

Filament: I used Bambu Labs PLA Tough for both the shelf platform and the brackets, 4-walls, gyroid infile, 15% for the brackets, 10% for the shelf platform.

Attach the brackets to the wall with expanding drywall screws or whatever is appropriate for your wall. I used the ones included in the photos which are E-Z Ancor Drywall Anchor #25410. You will need 4 anchors or screws. Here they are from Lowe's Home Improvement, but there are many brands and variations, these are just what I happened to have on-hand:

https://www.lowes.com/pd/E-Z-Ancor-EZ-Twist-N-Lock-75-100-pk/1001833728

The shelf is 9" x 9" x 3/8ths thick. This gives plenty of room for the router, as well as the cables that stick out a few inches. The shelf is offset from the wall with a 1/2" gap so that they can be fed through that gap between the wall and the shelf platform.

The flat shelf portion covers most of the available bed space, so has a strong tendency to warp, at least it did using BL PLA-Tough like I used. I had two failed attempts using the textured PEI plate, as it would stick to the plate fine, but curl the entire plate off the bed. I was finally successful using a garolite G10 plate from LightYear Direct, which is very thick and very stiff. This kept the plate from curling off the bed and resulted in a great print:

https://lightyeardirect.com/products/magnetic-garolite-g-10-composite-build-plate-for-bambulab-x1c-and-p1p

It did not require any adhesives, just cleaned very well with dish soap and hot water, then with isopropyl alcohol to remove any remaining oils. I set the bed temperature to 65 C as per LightYear's recommendation. The G10 plate is thick and VERY stiff. This will keep the plate itself from curling up off the magnetic bed. It's stiffness is the key to making this part of the print successful.

Note: I slowed down the printing speed to achieve decent results. With the long straight runs of the shelf, my go-to setting of using rectilinear infil did not seem to keep up with the stock printing speeds, and resulted in spaghetti fuzz from the infill. Additional, the side farthest from the AUX fan had issues with the far wall. The top of the wall was bumpy on the top surface, causing the hot end to drag noisily over them. So I slowed things down to:

Outer Wall : 100
Inner Wall : 200
Sparse Infill : 150
Internal Solid Infill : 200
Top Surface : 100

First Layer and First Layer Infill were left at 50 mm/s and 105 mm/s respectively.

I additionally used 10% Gyroid infill for the shelf itself, and 15% infill for the mounting brackets. Otherwise the slicing settings for the brackets and the shelf were the same. Gyroid is naturally slower than rectilinear, so that helped some also.

The above solved the speed, infill, and warping issues for the large, flat shelf platform.

The brackets were much easier, no special treatment was required for them. I printed them on the Textured PEI Plate.