Summary

I designed this to use a small cut of led strip (5050 or 5630).
In the photo it is installed on a Hypergo H14BM
For rear light I used RGB 5050 connecting only the RED wire. In this scenario the lights are not perfectly centered with the housing.
It is attached to the rear bumper with double sided tape.

I printed kt in TPU with th back face oriented to the bottom.

Feel free to modify as you like:

https://cad.onshape.com/documents/5744529290a8ddb46a9aa20a/w/7fab932e0e779fb2f2bc5eed/e/be0cfda03612b742b59bdd57

Have fun!