Hey Daniel! I double-checked the launch page, and it doesn't mention DisplayPort 2.1a in the official connectivity specifications. The monitor uses DisplayPort 1.4 with DSC.
The ROG Strix OLED XG27UCDMG is Asus' newest 27-inch 4K QD-OLED gaming monitor with a 240Hz refresh rate, 0.03ms response time, and G-Sync/FreeSync support, with advanced burn-in protection and USB-C 90W PD.