So, the thread stripped of my Kinesis Maxlight IX 15mm, meaning the end cap can’t go back on, meaning I can’t use it.

Cheaper to ask the LBS to lace in a new hub or sell the wheel for spares and buy a new one?

Unless the rim is something special or brand new I’d go with the latter, new hubs into old rims always seems like a false economy when doing it myself. But then if paying a shop RRP for everything then maybe just buying a new hub with matching dimensions to the old one and re-using the spokes and rim might save a significant wedge.

Assuming theres an axle through the hub.

And its merely a screw in spacer….

You could save some dosh by grinding out the rest of threads and making it a press fit with the axle through holding it together….

Agree with trail_rat. End cap isn’t doing much once it’s clamped. Bodge it back in and crack on.