Not true. You earn $1 MQD per dollar spent (less taxes) on Delta marketed flights (both DL and partner operated) if you credit them to the Skymiles program. But you must credit your flights to DL Skymiles program to earn that (you will get no MQD credit for flights if you credit them to FB program). It does not matter which credit card you use to pay for the flights. You still get the $1 MQD per dollar spent on flights.

You also earn $1 MQD per $10 spent on DL Reserve Amex card. You could conceivably earn DL Plat status solely by credit card spend on the DL Reserve Amex, but it would require spending $125K this year (and likely more in following years). $125K spend equals $12.5K MQDs + $2.5K MQD Amex Headstart = $15K MQDs. It's hard to know what to tell you here without knowing how much you typically spend a year on flights, what is your typical class of service, and how much you typically spend on your Amex card.