Hello @i0nium, you've described a couple issues with the Steam client instead of issues with SteamOS as a platform, so I've transferred this issue report to the steam-for-linux issue tracker.
The screenshot issue at #9479 needs to be resolved before looking closer at the available settings. Let's use this issue report to focus on the audio half of your feedback.
Nothing extracted yet.
Your system information
Steam client version: 1716584667 (&1714854927)
SteamOS version: 3.5.19 (& 3.5.17)
Opted into Steam client beta?: No
Opted into SteamOS beta?: No
Have you checked for updates in Settings > System?: Yes
Please describe your issue in as much detail as possible:
The option to save uncompressed screenshots and turn off screenshot notification sound cannot be found anywhere in both the Gaming Mode and the Desktop Mode.
Steps for reproducing this issue: