The Optane side of the drive used the same x2 controller as the pure-Optane cache drives. The NAND side used a Silicon Motion controller, same as their consumer

The Optane side of the drive used the same x2 controller as the pure-Optane cache drives. The NAND side used a Silicon Motion controller, same as their consumer QLC drives of the era. They almost literally just crammed their two existing consumer products onto one PCB and shipped it. Intel was never interested enough in the consumer applications of Optane to design a good, useful SSD controller around it, and they weren't going to let a third-party like Silicon Motion make an Optane-compatible controller.