I should have been clearer, I don’t mind the initial configuration, it’s the subsequent launches I want to be instant. That’s the feature I find most excellent on the Steam Deck: instant resume. You pick up your console because you have 15mn to kill and actually game 15mn.

This has not been my experience with Steam on desktop however. I don’t game everyday, and not all my games were on Steam (when I was still using it semi regularly), and I would invariably wait for Steam to update, followed by the various utilities and the games. And if it was a new machine, having to remember where to disable the damn ad popup …
With a fast Internet and playing often I’m sure it’s way less of an issue.
Oh and when I had network problems and it would take a long time before going in offline mode every time.

you can always play without updating if you want to

Can you? I never saw a straightforward way to do this.
I still have a partition running Windows for modded Skyrim, and the cardinal rule is never ever run it from Steam in case there’s been an update, which would mess up the modlist.

My other issue is ideological: I don’t think they do anything unethical but I don’t like having this private company’s always online closed source software running in the background on my computer.

Clearly people are happy with Steam, and as far as companies go it’s an okay one. I won’t argue with the AIO buying, installing, and the myriad of features.
However installing on Linux really isn’t that hard anymore.

1. Install the GoG (or Epic for the free stuff) game from Heroic Launcher
2. Play.*

Heroic is a better experience for installing, but I prefer Lutris, paired with lutris-gamepad-ui when not using keyboard and mouse. I made a little script to launch it when I turn on my controller, and turn off the controller when I quit. I’m in a game in a few seconds, even if I didn’t play in a month - when bluetooth doesn’t for some reason take 10s to connect

Even if some tinkering was needed, for a game I play often I would have spend less time waiting compared to using Steam.

*conditions may apply

Since the beginning of app stores and the release of Windows 8, Valve have seen the writing on the wall (see Apple v. Epic later) and realized they needed their own platform. It’s all about Steam OS.

The interests of Linux users and Valve merely coincide.

As for me, with a 99% single player games library, the most important thing is no mandatory launcher and no updates. Click, boom, I’m in the game.
So using GOG when possible.

Slay the Spire (1): Downfall.
It’s a free mod that transforms some bosses and normal mobs into playable characters. It’s very good, could absolutely have been the second Slay the Spire

ftfy