I just briefly had mine setup and almost the same setup as you but I ran the umbilical to the spot where the Z chain connects simply because I don't like the thought of wires on the outside of the printer.
BUT, going out next to the bowden is probably better if you are doing sensor less homing. I have lots of differant cables I tested for the CAN connection and most of Igus ones that are recomended were to stiff for the sensor less and they would prematurely trigger home. What I ended up using was this
https://www.amazon.com/dp/B0B944D6BY?psc=1&ref=ppx_yo2ov_dt_b_product_details
It was soft enough to run thourgh the Z chain but ridgied enough to stand up in the chamber. If it does end up falling over time I will had a keycard retractor to help it stay up.
Running to the exhaust port it should be in perfect position to stay up without getting snagged. I would add a PG7 connector to assist it.
I am going to add a couple links to nice connectors.
https://www.amazon.com/dp/B07YFQ7DFB?psc=1&ref=ppx_yo2ov_dt_b_product_details
PG7
https://www.amazon.com/dp/B078SSCKL...CKLJ?psc=1&ref=ppx_yo2ov_dt_b_product_details