Sonic Colors Ultimate launches into a black screen

**Game information**

[Sonic Colors Ultimate](https://store.steampowered.com/app/2055290)

**Distribution name and version where applicable**

Fedora 39 Silverblue/Kinoite

**Flatpak info**

`flatpak --version` => Flatpak 1.15.6
`flatpak --gl-drivers` => default, host

**Problem description**

When launching Sonic Colors Ultimate in a flatpak'd environment, the game either launches into a black screen with GNOME complaining the app is not responding or into a black screen with an orange-ish mouse cursor.
Here's the log for the game, run with PROTON_LOG=1: [steam-2055290.log](https://github.com/flathub/com.valvesoftware.Steam/files/13789820/steam-2055290.log)
There is a related issue on flatpak'd Heroic Games Launcher, as seen [here](https://github.com/Heroic-Games-Launcher/HeroicGamesLauncher/issues/1943).

**Does this issue reproduce with native Steam**

No, at least when run on a Steam Deck.

Start by reviewing steam-2055290.log from the PROTON_LOG=1 run and compare the behavior with the related Heroic Games Launcher issue. Check whether the failure reproduces outside the Flatpak environment, including the reported native Steam comparison. Done means identifying the cause of the black screen and documenting or validating a fix for Sonic Colors Ultimate.

Written by the indexing model from the issue text.