Is this a good deal on a 2020 BMW 740i

That’s the money factor

You need to confirm what numbers this dealer is using.

Also need to confirm if that MF is for one pay or 36/10.

One pay ≠ huge down payment. One pay money is not at risk, it’s basically sitting in a virtual escrow account from which a portion is withdrawn monthly through the term of the lease.

I think the monthly payment is too high. I think you can haggle a bit more or put more down. Good luck!