Got the answer myself:
So before paying real money to buy a monitor, I bought a HDMI dummy dongle. I can use the edid-rw to write a fake EDID to the dongle, plug it in the DisplayLink port, and mirror my real monitor to the dummy to check result (also use BetterDisplay's display information page).
- 3072x1920 (16:10) : HiDPI is enabled at 1536x960.
- 3200x2000 (16:10): HiDPI is enabled at 1600x1000.
- 3240x2160 (3:2): No HiDPI available at whatever supported resolution.
Screenshot 2026-01-18 at 11.44.34 PM.jpg