Yes, I know there are ways to run GoG games on Steam Deck. But here’s my case: most of my games were purchased on GoG, mainly because it is way cheaper in my country. I do have consoles and I don’t bother buying too much on Steam. So I have a lot of games like Cyberpunk or BG3 on GoG. I would love to have an official way to run GoG games and a certainty to run my games on a Steam Deck, otherwise I will have to start over I guess. Unless someone tells me that trick found on github has zero flaws and I can run my games fine.
With this you can play your GoG games and EPIC games, not sure if there’s support for everything but I also haven’t checked in a while https://heroicgameslauncher.com/
And there is a Flatpak of heroic launcher available on SteamOS through the store.
I use it for my gig and epic libraries and it works seamlessly and has a 1 click Steam export function to add all your games to Steam.