[Help] Sober (Roblox) grey thumbnails & infinite loading on CachyOS Hyprland (GT 710 / Nouveau)

Hey everyone,

I'm having trouble getting Sober (Roblox Flatpak) to load game assets or join servers on CachyOS running Hyprland.

The issue:

• The client opens, but game thumbnails, avatar icons, and UI elements remain as blank grey boxes.
• Trying to join a game hangs indefinitely on the "Waiting for an available server" screen.
• Note: This exact same system worked completely fine when running CachyOS with KDE Plasma (Wayland). The issue started after switching to Hyprland.

System Specs:

• OS: CachyOS (Arch-based)
• WM / Compositor: Hyprland
• GPU: NVIDIA GeForce GT 710 (Kepler architecture)
• Driver: nouveau (Open-source)
• Install method: Flatpak (org.vinegarhq.Sober)

What I've already tried:

1. Flatseal Permissions & Sockets:
   • Toggled between wayland, x11, and fallback-x11 sockets.
   • Confirmed Network (net) and Inter-process communication (ipc) are ON.
2. Portals:
   • Installed xdg-desktop-portal-hyprland and xdg-desktop-portal-gtk and restarted portal services.
3. Network & DNS:
   • Disabled IPv6 on my wired connection via nmcli.
   • Forced Cloudflare DNS (1.1.1.1 / 1.0.0.1).
4. Cache & Launch Flags:
   • Purged Sober's asset cache (~/.var/app/org.vinegarhq.Sober/cache/*).
   • Forced X11 backend via GDK_BACKEND=x11.

Since this setup worked fine under KDE Plasma Wayland, is there a specific wlroots / Hyprland buffer or EGL issue with older Kepler GPUs running nouveau? Has anyone gotten Sober running on Hyprland with legacy NVIDIA hardware, or is switching drivers/compositors the only fix?

Any advice or workarounds would be appreciated!