There are "square" wire chases sold
stores, that are actually lengths of steel
(painted) shaped like 3 sides of a square, that are then snapped into clips mounted on a wall. The result is a neat steel chase, which can be popped off the backing mountings to access the wires if need be. They are NOT intended for any type of regular periodic maintenance
, just for access when or if needed.
But you should be able to find that very easily.
An alternative would be to use either metal or pvc conduit and junction boxes, and just run the wires through the conduit. Might be "good enough" depending on how many junction boxes and turns you have to make.