Welcome Axl,
Thank you for the clear description and for listing what you've already tried. Please try the steps below. They are different from the ones you have already done.
Step 1: Recalibrate each display while it is the only active display
- Press "Windows + P" and select "PC screen only", so the Odyssey G60SD is the only active display.
- Go to "Settings" > "System" > "Display", select the Odyssey, and make sure "Use HDR" is "On".
- Open the Windows HDR Calibration app on that display, complete all the steps, and name the profile clearly, for example "G60SD-400".
- Click "Finish" and check that the message "Color profile associated" appears.
- Press "Windows + P", select "Second screen only", and repeat the same process for the S90F (for example "S90F-1200").
Step 2: Remove old monitor entries so Windows detects both displays again
- Right-click "Start" > "Device Manager" and expand "Monitors".
- Right-click each of the two monitors > "Uninstall device". Do not tick "Attempt to remove the driver for this device".
- Restart the PC with both displays connected. Windows will detect them again.
- Warning: Windows may remove the profile associations for these displays, so you may need to repeat Step 1 afterward.
Step 3: Update Windows, the graphics driver and the calibration app
- Go to "Settings" > "Windows Update" > "Check for updates" and install everything available, including optional driver updates.
- Install the latest NVIDIA driver for your RTX 4090.
- Open the "Microsoft Store" > "Library" > "Get updates" and update "Windows HDR Calibration".
- Restart the PC, then test again with "Windows + P".
Looking forward to your update.