I had this code a few times, although my brake never stuck on. I was able to eventually get it to clear the first two times by performing the parking brake calibration in forscan. The last time I couldn't get it to clear, so off to the dealer. They ended up finding the seal had not been...
FTL5212. Everything seems fine with the angles but I wasn't really concerned about them either, as there are several similar spacers on the market with the same lift height. Alignment was within specs as well.
Mine takes a while for the level to come up after shutting down. Manual states to wait 15 minutes for an accurate reading. If I wait long enough the 7 qt recommended fill only reads a little above 1/2 on the dipstick.
Looks like you pressed the limit button on the left side of the steering wheel, which means the truck won't go over 20. Press it again and it should turn off and to back to normal.