Agreed with dinanm3atl, Amex Platinum for 25k/50k bonuses of 10k/20k MQMs respectively, or Amex Reserve for 15k/30k MQMs boost annually with MQDs taken care of at $25k spend.
Then it's up to your travel pattern to hit your MQMs or MQSs for the level you want/need.
My wife and I had been platinum for several years, then got close enough that the Amex Plat till care of our spend and the bonus MQMs put us both at DM level the past two years, which is where Delta seems to still value that status.
With your 50% bonus on MQMs for every route you take, you should be able to obtain DM status...depending on your routes/frequency.
Otherwise, as dinanm3atl suggested, hit a mileage run to compensate any MQM shortage...I'm heading to SAN to see me oldest daughter to stage myself out of LAX to run thru ATL-MSP-NRT-SIN and return for 29k miles (4-5 countries in three days) for around $500 using points and vouchers to maintain DM and its perks.