[KY_GMC]

I'm not an expert on this but I had a similar experience when I did my axle flip.

From your numbers, your angle are too high. You don't want more than 3 degrees difference between each flex point, but you need at least 1 degree of angle so that u-joints are moving during each rotation, you don't want them perfectly straight. And you want the rear end angle to match the front drive shaft angle.

I would remove the spacer from transmission and see what the angle is at proper bolt torque (if it has rubber mount).

Then adjust the carrier bearing support to get the angle between the front shaft to transmission between 1 and 3 degrees.

With that set, I would adjust the rear end angle to match the front drive shaft.

From here, your angles should be good.

I would guess that since the front shaft was at 6 degrees that it was putting a severe angle load on the bearing and caused it to fail.

If you do a search, there are many posts here that have links to more technical discussions.