This is the way. Routing decks is asking for trouble.
I also agree that braid should be avoided.
I’ve never had any issue with long phase wires but i’ll be fucked if every time i’ve extended sensor wires i haven’t lost my sensors soon after.
I don’t know what it is, I’ve never had the patience to troubleshoot it, but i’ve extended sensor wires quite a few times now and every single time i’ve ended up just running sensorless.
If you insist on routing the deck, I would highly suggest fiberglass over the wire when you’re done, this can add some strength back in a way that retains flexibility. It makes maintenance all but impossible though.
I’d wager soldering 6x 18AWG is a skill issue for most people, especially if using connectors as an intermediary like an LP20 or something. Such thing wire and so little insulation it’s bound to fuck up somewhere.
Instead of extending I’ve had better results just installing longer wires to the motors.