Hi,
I have to be honest, the most common cause of what you described is dirty, loose, or damaged battery terminals. What I have seen happen is this. The car will not start. You place jumper cables on the terminals which tightens the terminal and then it starts. Once you disconnect the terminals, the car stalls because it loses connection.
Lets start simple with this one. First, I realize you have a new battery, but follow this link to see if you find anything and if it helps.
https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked
Let me know what you find.
Take care,
Joe
Monday, April 20th, 2020 AT 9:06 PM