Hi! I feel your frustration. I can't stand a car not working that stress me awfully bad!
Same problem here, 2015 SXT Journey. After a few cold days last Sunday it acted exactly as you described. We bought a jumpstarter at Walmart (Stanley 1200 amp with usb, light, coffee maker, and what not!) and after a new tries it started. Used the car perfectly for the rest of the evening turning it off and on several times. Monday morning same thing, today, same thing. Wanted to buy a battery at my local walmart but they didn't had the appropriate size.
Now reading that Walmart (or cheap brand batteries in general) are not a good idea.
What happened to yours? have you changed it? If so, which brand did you bought? Hope everything is better now.
Thank you for sharing your story with us.
Chopper