Belkin INC007 dock — only 1 of my 2 monitors gets a signal (macOS Tahoe 26.6, M5 Pro)

[Hakan]

Hi all,

I'm stuck on a dual-monitor issue and could use some help.

My setup

MacBook Pro, Apple M5 Pro
macOS Tahoe 26.6 (25G72)
Dock: Belkin CONNECT Universal USB-C Triple Display Dock (INC007)
Monitor A: Dell G3223D (2560×1440) — DisplayPort
Monitor B: Dell G3223Q (4K) — DisplayPort
Both monitors go through the dock; the dock connects to the Mac with a single USB-C cable

The problem

Only the G3223D works. It's detected normally and runs at 2560×1440 @ 144 Hz.

The G3223Q gets no signal at all — the monitor never wakes up, and System Settings → Displays shows only a single external display. Same result whether I power the Q on before or after the Mac.

One odd detail: my menu-bar brightness utility does list both monitors by name, even though the Q never shows a picture.

What I've already tried, with no change

Unplugged and replugged the dock's power adapter
Unplugged and replugged both DisplayPort cables
Rebooted with both monitors connected
Swapped which dock port each monitor is plugged into

Has anyone run into this with this dock, or with two monitors on Tahoe in general? Any suggestions on what to check next would be much appreciated.

Thanks!