I finally got some time to order a few new parts and get out to the range. Thought I would post a final reply of what actually worked for me in case someone else is searching about the issue and could use this.
After the H2 buffer AND Wolff XP spring didn't work I was considering an adjustable gas block. But with a 12" DD lite rail (and pinned AAC muzzle brake) it would have been throwing out hundreds of dollars. So, I went over to heavybuffers.com and picked up their 8.25oz "XH" buffer. Last resort pretty much.
Took it to the range and it locked up on like the 5th shot.
The rifle had an auto BCG in it, but I had a semi carrier floating around in my bag also. Never thought to use the semi carrier since it's lighter and didn't make sense that it would help to make that lighter. But, the spring and the crazy heavy buffer didn't help and the gun would not shoot reliably so I tried it just for kicks- fully assuming it would fail immediately.
A few hundred problem-free shots later, and a HUGE smile later
I'm confident the problem is fixed. Thank you guys for all your help with the suggestions of springs, buffers, BCG's, etc. I'm oh so relieved this thing is working now!