No supports needed.
Push the strip gently and precise, especially in the corners.
I used PLA, but every common material should be fine.
LED Stripes:
https://de.paulmann.com/p/usb-led-strip-neon-colorflex-blau-1m-4-5w-10lm-m/70564
Neon Feather:
https://www.printables.com/model/185553-neon-feather-led-strip
The author hasn't provided the model origin yet.