Created attachment 181213 [details]
Relevant crash log

### Summary

Wayland session fails to start with KWin 6.3.5 on NixOS using NVIDIA GPU and quad-display setup (All GPU outputs populated). Session aborts early when 4 monitors are connected via DisplayPort and HDMI to an RTX 4090.

### Steps to Reproduce

1. Boot into a Wayland session with  NVIDIA RTX 4090
2. Have four monitors connected via DisplayPort and HDMI
3. Attempt to start a Wayland session

### Observed Result

```
kwin_wayland: Invalid framebuffer status: "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"
kwin_wayland: 0x502: GL_INVALID_OPERATION error generated. <image> and <target> are incompatible
kwin_wayland_drm: Checking test buffer failed!
```

These messages repeat continuously until the system becomes unresponsive. A hard reboot is required.
No desktop appears, session fails.

### Expected Result

KWin should initialize the session and handle display configuration.

### Hardware

- **GPU**: NVIDIA RTX 4090 (proprietary driver)
- **CPU**: AMD Ryzen 7 5800X3D
- **Motherboard**: B550M AORUS PRO-P
- **Displays**: Four monitors connected:
  - 2× 1920×1200 @ 60Hz (DisplayPort)
  - 1× 1920×1080 @ 60Hz (HDMI)
  - 1× 2560×1440 @ 360Hz (DisplayPort)

### Software/OS Versions

- **Operating System**: NixOS 25.05 (Warbler) – `25.05pre797896.d89fc19e405c` (Unstable Channel)
- **Kernel Version**: 6.12.28 (64-bit)
- **KDE Plasma Version**: 6.3.5  
- **KDE Frameworks Version**: 6.14.0  
- **Qt Version**: 6.9.0  
- **Graphics Platform**: Wayland (default session)

- **Driver Version**: 570.144 (proprietary)
- **CUDA Version**: 12.8
- **Vulkan Support**: Verified and functional
- **GL Support**: Verified via `glxinfo`
- **nvidia-smi Output**: Shows active workloads and correct memory usage

### Reproducibility

100% reproducible on boot with four monitors connected.

### Notes

- This issue does not occur with X11 or three-monitor Wayland sessions.
- All hardware and driver components (NVIDIA driver, CUDA, Vulkan stack) are correctly installed and functioning in X11 sessions and gaming workloads.
- The system uses the proprietary NVIDIA driver (`hardware.nvidia.open = false`) with modesetting enabled, VRR and G-SYNC environment variables exported, and 32-bit support enabled for compatibility.
- `boot.kernelParams` includes `nvidia-drm.modeset=1`.
- This issue has been reproduced across multiple distributions, including Nobara, Debian Unstable, and openSUSE Tumbleweed, suggesting it is not specific to NixOS.