Usually for longer runs of LED strips I power them from the middle. Specifically I cut the strip in two and put the power and data for both in the middle making handling the wiring much easier. It does make controlling the individual LEDs a little trickier but it works. I am looking at about 10-12 feet of strips so cut in half is 5-6 feet each. Past experience shows that I should get good power saturation at that length without much voltage and brightness drop. As to where I’m going to put the controller and power supplies, I initially thought I could find something I could completely hide but now I think something like a 9” in wall media box will work and then just come out of the panel with the normal plug for power. The biggest problem I have is there are no outlets on the stairs, nor near the top or bottom of the stairs. The closest is on the other side of the upstairs hallway. Not a long distance but putting a wire / cord across a traffic lane doesn’t bode well. However I just discovered that on the other side of the wall near the top of the stairs is an outlet so I will put the box in the wall next to the outlet, come out the front of the box with the 120v power cord from the “laptop brick” and then go out the back of the box with low voltage and data wires to the strip(s). As to my controller, I’ve used raspberry pi a lot too but they are big,chunky, and draw a decent amount of power so 24/7/365 just to run one set of lights is overkill. But a little ESP32 controller https://heltec.org/project/wifi-kit-32-v3/ can do everything I need, sip power, and cost less than even a pi zero. I am considering a Pi Pico W but the ESP32 also has the needed WiFi AND is supported by the WLED https://kno.wled.ge/ project making is very easy to control the LEDs.