Regarding the ‘keyboard and mouse’ part in your post … I use a wireless set. So the rPi is mounted behind the monitor and only has 2 wires on it: power and HDMI. There’s a USB dongle plugged in that’s for the keyboard and mouse which I rarely use. Specially since I log in remotely. The only time I need the mouse or keyboard is if something bad happened and the rPi won’t boot up normally. But other than that, not needed.