I don't have an answer for you Austin but this did prompt me to wonder (again) why some manufacturers stopped/didn't use studs and brass nuts. I used to work in a muffler shop and Toyotas were great because they had studs and brass (they were quite red and light so maybe a high(er) copper content) and were never a problem to remove.
Clamp a vise grip on it and pull and tap with a hammer.
Slide hammer with a hook attachment to grab inside and just take it easy trying to get it out.
If it breaks, just find a turbo rebuilder in your area and see what he suggests.
Not a big deal if the 5M2824 coupler breaks. Their available aftermarket...Florin shows 17 available.
possum piss lots of and plenty of time for it to work. and work gently.