Hello @ralgar, this was previously requested at #8711 and the response at https://github.com/ValveSoftware/steam-for-linux/issues/8711#issuecomment-1197050595 is equally valid today as it was back then.
Thanks for the reply @kisak-valve, and my apologies for not noticing the original issue.
I will respect Valve's decision, whatever it be, but I can't say I agree with the validity of your reasoning. I hope you'll at least consider putting out some feelers internally over these concerns.
Edit: I think I've found a way to achieve this, while remaining online and not affecting other games. At the end of the day, it is my system that this software runs on, and I am the supreme authority over it. Thanks for playing :)
This isn't a Linux-specific issue, more of a general QoL feature request that I didn't know where else to post.
The Issue
As many people know, Skyrim SE was recently updated again - an update that nobody asked for, almost solely for the purpose of attempting to shoehorn pay-to-play mods into the game. The immediate effect is that anyone with a noteworthy mod list has been left with a broken game again, and the need to somehow downgrade their game files again.
I know there are a variety of ways available to downgrade/restore the game files (filesystem snapshots, depot downloads, etc), but that doesn't make it any less inconvenient. Not only do we have to manage downgrading/restoring the game files, but we also have to run Steam in Offline Mode any time we want to play - to prevent it updating again.
This is such a common problem for the community that "downgrade patchers" had to be created for the game, which frankly is an insane solution to a problem that should simply be resolved at the source.
Of course, some less technically inclined users find any method of downgrading the game to be rather difficult. There are countless help requests on various community social platforms at the moment.
This is probably the single most frustrating issue with modding Steam games. For those of us with limited time available for gaming, it often results in us choosing not to play the game at all - which is completely unacceptable.
Proposal
I would propose that a new option is added to the per-game update settings in Steam - a "never update this game" option. IMHO, this is an important QoL feature for any moddable, single-player/co-op game.
Hopefully there aren't any logistical blockers to this. I would like to think that multiplayer game servers already have some baked-in ability to reject out-of-date clients, in case this feature is incorrectly used.
If you wanted to go even further with this feature, I'm sure users would also welcome the ability to select the specific build/version of the game they'd like to have installed.
Other games that would benefit from this
And probably others that I'm not aware of...