the heroic launcher was recently updated to support gamescope (installed it through flatpak by installing org.freedesktop.Platform.VulkanLayer.gamescope 23.08 through the terminal using >flatpak install).
it can be configured with a simple GUI (as seen above) and gives you all the options you could reasonably need. One of the big improvements is that on wayland, unlike when used through steam, it will actually close the game when told to, without requiring you to maunally kill the gamescope process.
valve still requires you to edit text launch options to enable and configure gamescope.
Valve needs to do better with gamescope, this 3rd party FOSS app is embarrasing them.
Gamescope is a microcompositor from Valve that is used on the Steam Deck. Its goal is to provide an isolated compositor that is tailored towards gaming and supports many gaming-centric features such as:
-Spoofing resolutions -turning off VSync on Wayland desktops -using HDR -Upscaling using AMD FidelityFX™ Super Resolution or NVIDIA Image Scaling -Limiting framerates
In particular, gamescope is rendered seperately to your entire desktop, meaning that certain problem games that may have issues when rendered by your normal compositor (wayland or X11) may work fine under gamescope. For instance: certain games may have jerky mouse input or frequent crashes when running under wayland, but those issue may disappear when running within gamescope.
(this is also why we call gamescope a micro-compositor, as it runs seperately to your main compositor that handles your desktop e.g. Wayland or X11)
https://wiki.archlinux.org/title/Gamescope