They always fall apart. Double nut the stud that holds the cap on or spot weld the cap to the rest of the muffler. I have had the stud break after it was double nutted. So spot welding is best in my opinion.
assuming the header is still intact (i cant image it wouldn't be) you can just hacksaw the muffler off and build you own pipe from there.
if anyone gives you a look and asks "why is you exhaust made from random lengths of electrical conduit, hose clamps, and hope" you can simply tell them that it's custom work and they are cretins.
fortunately exhaust work is really easy to break into even without a welder.
my huasheng is breathing out through a header comprised of a spare flange and two inches of pipe I happened to have, then a soup can joint with two hose claps to another three inches of pipe to make a bend (this bit touches my frame so theres a slice of heater hose jammed between the pipe and the frame) then I have about five feet of heater hose before the straight section thats hung from the underside of the bike. this straight section had a bit of stainless steel pot-scrubber crammed into it for quietness.
works great, better than the factory muffler (but that thing belonged on a mower anyway)
In reality, you can do almost anything you want with your exhaust. The smallest inside diameter point you make is the restriction, and usually, the longer the quieter.
Use the search bar at the top of your screen, try different wordings, and you should have more info than you need.