That's a big yikes.. but not surprising. Also, it's a key piece to as why GM is halting Apple CarPlay for the EV's (and all others soon I'm assuming). It's well reported that Apple will essentially own that data, and leaving the automaker to deal with whatever apple wants to do with it.. and...
New to me.. worst case unplug the batteries for about an hour and plug them back in, but since you're this close I'd take it in and have them look at it.
I'm using 5100's on the 2" section, 1 down from max. Most agree that if you don't offroad often and you don't go with 2.5" setting you're probably fine without UCA's.. however, as always, it doesn't hurt.
Get a test light to find the hot lead and get a tap fuse kit and hardwire within your headliner.. that's my plan once I get over my injury. (just a few more months hopefully).
It's been really, really cold here the past 3-4 days, lows being around -5 for a day or so overnight (I'm in TN) with no added fuel additives and I didn't gel. I was surprised to be honest, but weird how yours did. I know some states will do a blend during winter, but I'm not sure how strong...
I've personally never been a fan of that company, it's always been "snake oil" to me. I would look at legit tuning if you're wanting something more.. granted, with any tuner you run the risk of voiding the warranty.. but that's the risk most of us have taken... :D