I wanted something that I could mount the Raspberry Pi on the wall but still have access to the Pi's GPIO, power, USB, and other connections. Getting to the SD card still requires removing the display cable, but that is easy.

You will need some M2.5 screws to mount your Pi.

The USB-C connector I am using to power my Raspberry PI 3 Model B+ and the 7" Touch screen is https://amzn.to/3WJPtua, and this cable is excellent: https://amzn.to/3Z8B4Jm It can power both the Pi and the Touchscreen with a single cable and with no low power warnings.