Original thing:
Cable channel that clips onto 2020 v-slot extrusion as in 3D printer frame. Print in vase mode with nozzle diameter set to 0.5 or set extrusion multiplier of 1.25 so that you get some over extrusion. It is designed for this!!
Remix:
Inner corner variant
Cable entry variant

Prusa i3 Bear Upgrade 2.1

No

No

0,2

20