If you know anybody who 3D prints, that may offer a solution.

I’ve printed custom wire reinforcements in TPU. They are very flexible, and they will take the strain off the wire itself.

Any crimped or soldered joint is going to be a weak point. So if you can’t find something strong enough? Make it!

If you don’t know anyone who has one, you could check thingiverse.com and printables.com for a model that meets your needs, and there are plenty of print services who will make them for you.

I do have a 3d printer but, that one is currently sadly unable to print anything else than PLA (it’s a craptastic old anet a8) and I don’t know anyone at least close by who can do TPU. There is one thing I forgot to add to the original post, one additional reason I want to get something else than RCY is because of the jagged edges. They to tend to get caught in the fabric every know and then. But thanks for the advice so far, I will consider it.

Have you tried tpu? Googling says it works on the A8.