I have done stuff like that but I don't know if my work is good. One tip is to use resistance heating for the center pin solder point, so you don't get solder on the outside of the center pin, so it seats perfectly, or to buy the proper crimp tool and do a magnifier inspection before you crimp.
But I suppose that is the easy part. Measure everything with calipers and work slowly. If you miss 1 strand on those center pin crimps, they will slide right off! Recommend you buy the go-nogo gauges too for that kind of work. I thought I was going crazy or the instructions were wrong before I verified with the go-no go gauge and discovered I was losing a wire that was nearly invisible that made the crimp slide off., expensive lesson.
Being precise with braid and foam = pain in the ass. Ensure all tools are basically in mint condition for a start and use fine tip markers (you can get quite fine markers in the art store) and then caliper for verification, with all work done under magnification. Also you need fixture for the cables when you work on them. Inspect for damage and disorder after every step.
Ship in bottle type work.
But IMO easier then making a good pizza. Reminds me a bit of manufacturing a picture perfect sandwich, its all kind of unstable, where the lettuce is the braid. Or maybe a hot dog
And clean all the parts before assembly too IMO, and the work surface too, I used gloves for the most expensive connectors too.
The foam is not the worst one either I think, the teflon tape wrapped ones (like plumbers tape) is IMO even worse.
Do I blame you for looking for a assembler? hell no. Might come out slightly cheaper if you don't screw up. I think its satisfying though.