Mark, I’ve started experiencing the same issue with my 2020 Gladiator. The situation is identical to what you have described. The exception is no matter how hard you push on the firm brake pedal, it will not start. The only work around I’ve found is connecting my Jump Box to the battery...
I just ordered Black Rhino Fury’s 20x9.5 in Gunmetal. Tires will be TOYO Open Country M/T 35x12.50R20. It will also be getting a FabTech 3” Lift with Stealth Shocks. I’m hoping the shop calls this week to say everything has arrived!