A carefully aimed MAPP gas torch got it free after what seemed like 1hr+ of manual hammering.
I got the 2 12mm retaining bolts free with the steering wheel straight, then turned it to the driver's side about 1/4 turn until it locked itself. This aimed the seams in the collar right at me through the fender well gap. I went to town with a chisel and eventually pry bar to open the collar as much as possible.
Once the collar was theoretically no longer clamping the splines, I hit it with the torch. A lot.. I made sure to keep the piece nice and hot as I worked every angle possible to get it to slide up the steering column shaft.
The collar eventually cleared the intermediate shaft and I was able to fully remove it from the steering column splines. Getting it off only took a few hits since I could smack it from the top of the engine bay with no obstructions.
I made sure to antiseize the collar pretty good before reinstalling on the new intermediate shaft. I actually had a harder time getting the lower part of the shaft off the rack side even though the top was totally free due to fatigue, no clear shots, and no air hammer. Heat was my friend here too. Penetrating oil didn't do anything besides make my garage smokey.