but still couldn't make it line up right without pushing on the case. So it could still be a seating issue, even though the retaining clip is fully engaged.
The GPU was not seated fully, the two prongs on the bottom of the mounting bracket were getting caught on a metal seam below the motherboard. The prongs were not perfectly straight, slight angle on the tip towards the perimeter (seam) of the case. Not sure if that's by design but it compounded the issue with the seam. I was able to correct this by slightly bending the prongs straight again, If your going to do this, use 2 wrenches, one to bend the tip and one to stop the rest of the bracket from bending. I also had to fix the top bar on the case bracket which had been bent upwards to accommodate the GPU misalignment.
Once I was done, I put the card back in and it seated perfectly without effort. Everything lined up perfect and you could see from behind that both prongs made it past the metal case seam. I tried to reproduce the crash all last night and today, but it seems to be gone now. Normally I get this crash on games like valhiem and stranded deep in the first 15 minutes of gaming each day and sometimes multiple crashes. Now it runs perfect.