I think the tech is full of it and talking out their backside. I would feel free to ignore everything they said. I see no way that disabling ESS could be harder on the batteries than leaving it enabled. We’ve seen quite a few batteries replaced under warranty, so I think Chrysler is simply sourcing cheap, low quality batteries.
It is my observation that short local drives will result in the ESS disabling itself with the message “battery charging” in the status display. I live in a small town where nothing is more than 10 minutes drive away. A longer highway drive usually restores the ESS function, though not always. Regardless I’ve never had a dead battery, no start, or any odd operation because of low voltage. My van is a 2018 Touring L, currently about 9 months old and 13k miles.
I have on two occasions left my van parked for 20+ days while out of the country. On both occasions it fired right up upon return, though ESS was disabled due to battery charging. And I never attach a battery charger.
In my observation, battery problems are not unique to the Pacifica. There are lots of no-start complaints over at the Honda Odyssey forum as well. My wife bought a Subaru Outback, and the undersized batteries in those went dead all the time, to the point that Subaru released a software update to charge them more aggressively. And quite a few dead bats reported in my Ford Focus forum as well. I think these new cars are just tough on them, given the plethora of electronics and electrical devices.
My long winded $0.02.