HDR unavailable on docked ROG Ally Z1E

[Segagaga-Steam]

Your system information

• Steam client version: 1778281814
• SteamOS version: 3.7.24
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

Getting a "Current Display does not support HDR" message when docked on external monitor. I have taken steps to ensure all hardware meets the standard. I have a direct connection between the ROG Ally, Dock and TV. I bought new HDMI 2.1 cables. TV is a "Telly" brand 55in TV. PS5 with HDR works as expected. To rule out the weird TV I also tested on a 4K Roku TV. Same issue with HDR.

HDMI cable: Tested with official PS5 HDMI 2.1 cable and other 2.1 brand cables.

HDMI cable link: https://www.walmart.com/ip/8K-HDMI-Cable-2-1-6FT-2M-Slim-48Gbps-High-Speed-Braided-Cord-4K-120Hz-144Hz-8K-60Hz-HDCP-2-2-2-3-Dynamic-HDR-eARC-DTS-X-RTX-3090-Compatible-Projector/16083910589

Dock: iVANKY ROG Ally Dock @4k 144Hz refresh rate via HDMI 2.1

Dock link: www.amazon.com/dp/B0G5QKBV37?th=1

TV site: www.telly.com

Steps for reproducing this issue:

1. Load up SteamOS on docked ROG ally Z1E.
2. Navigate to display settings.
3. HDR option is grayed out.