The symptom set you earlier documented contains the signature of a bad battery. This is how many people describe the failure, and I've seen this three times myself. Most vehicles nowadays contain some form of intelligent battery monitoring. The give away is when the starter won't engage, won't start with a jump, and nearly every cluster lamp is illuminated. The intelligent battery system has sensed a battery that cannot supply all the current necessary to properly function all of the other systems and locks into the load sharing mode, which because of the faulty battery will not allow the starter to engage.
It would've been nice if you could've measured the battery terminal voltage with a shop quality digital voltmeter to verify the condition.
As to the dealer saying they can't warranty a battery...you're dealing with the wrong people!
Best regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33 gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 03 June 2018. Now at: 044824 miles.