Post-Login Screen Disconnection and 3:2 HiDPI Scaling Failures

[CISHENZF]

Hello

I recently purchased a DisplayLink dock and encountered some issues. Here are the details:

DisplayLink Product:
• Chip: DisplayLink DL-6950
• Ports: HDMI 2.0 × 2
System & Monitors:
• OS: macOS 15.3.1 (Intel processor)
• Monitors: Two 14" portable screens with 2160×1440 resolution (3:2 aspect ratio, non-standard size).

Issues:
1. Screen Connection Behavior:
1.1On startup, both external screens work normally until I enter the login password. After logging in, the screens disconnect (lose signal) and only reconnect once the DisplayLink Manager software launches.
1.2DisplayLink Manager fails to detect the screens: "No DisplayLink-enabled display detected" (even though they are functioning).

2. Resolution & Scaling Issues:
2.1The native resolution (2160×1440) is too small for the 14" screens, making text unreadable.
2.2macOS display settings lack 3:2 scaling options (e.g., 1440×960 HiDPI).
https://postimg.cc/CB0mjFyk

2.3Tried BetterDisplay and SwitchResX 4.14.0 to add custom resolutions, but neither worked:
In SwitchResX, no "Activate immediately" option appears (unlike my Dell U2723QE/U2719DS displays).
https://postimg.cc/mzSVj0Rq
https://postimg.cc/Lg6DbN8s

Failed to enable HiDPI or add custom resolutions.

Please help resolve these issues. Thank you!