https://www.bimmerworld.com/BMW-Engine-Oil/
This website states their table of "acceptable" oil consumption data from BMW is 1 liter per 1,500 miles for B58 lol. It sounds pretty ridiculous but if it really came from BMW, I would assume the dealers are told the same thing. It also talks about "break-in" period right below their chart where BMW advises not to be too concerned about oil consumption during the first 10,000 miles.
I really dislike how this car initially burns/consumes oil, but I wouldn't waste time with the dealer if they are reluctant to look any further into the car.. Luckily my dealer has been helpful and did a full measure of the oil when they drained it during my last visit. They did a complete oil change during the visit and asked me to return after 2,000 miles to measure the consumption. Fingers crossed that the "break-in" is really true.
FYI, I topped off my oil the first two times the warning came on and even bought a case of oil to avoid inconvenience of visiting the dealers. I visited the dealers when the warning was not even on and they still helped me. If anyone is in the Socal area with the same issue, I would recommend Irvine BMW