https://reprap.org/forum/read.php?397,868561
Because I am not now in a position to build from scratch, I posed a question about a commercial corexy that could be improved. I was thinking along the lines...
kitrailcore
https://www.printables.com/model/628433-railcore-ii-zl-x-ldo-smart-orbiter-v3-x-euclid-pro
railcoreiizlxldo