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.
I mean...you're mostly right, but I don't know how setting a few flags like -H,-W,-h,-w is that big of an issue. I agree lutris and maybe heroic (I don't use) have frontends for these,but I would hardly that "way better".
Edit: grammar,typos
it's incredible how out of touch this community is with the average end user. I'd wager that MOST people don't know how, much less want to set custom flags for every one of their games. Believe it or not people actually like using nice GUIs and rely on simple intuitive frontends, and it's a massive failure on Valve's part considering they're the largest, most mainstream PC gaming platform.
Nobody running a FOSS third party launcher is an average end user. Also, people routinely add flags to typical games even on Windows (e.g. -skiplauncher)... It's really not that big a deal.
Yeah. I don't know what those flags are... Yet.
The moment a game launch fails in that particular way, I will be diving all the way into that particular deep end.