Delta occasionally brings back a feature called which allows eligible members to purchase MQDs directly to reach the next Medallion tier.
Members with at least 100,000 rollover MQMs could choose to extend their current 2024 status by one year for every 100,000 miles.
Since you can no longer buy MQMs, you can "buy" your way toward status using these MQD-earning features: Delta Medallion Status: What You Need to Know - NerdWallet
You could convert MQMs to MQDs at a 10:1 ratio (e.g., 10,000 MQMs = $1,000 MQDs) to help reach a higher status tier for the following year.
Typically offered as a limited-time program toward the end of the year.
If you have a leftover balance of MQMs from 2023, Delta provided a one-time feature to convert them through December 31, 2024. While the deadline for selection has passed for many, the options included: