"Better Audio" is always a very subjective/relative thing and even in the world of Steam Deck, not all speakers are created equal. However, according to most community members, this will have a "huge difference in games with music and general music with exposed treble, it tones down the harshness and balances the sound out"
Follow all of the instructions below for the preferred audio setup(don't skip any steps).
Download and install the following software:
At the end of the install, it will ask which device to be assigned to, we want the "Speakers" of the "AMD Audio Device"
After clicking OK, say "I want to manually reboot later"
Download the following config file, extract it to C:\Program Files\EqualizerAPO\config, we will use it in the next step:
Peace Steam Deck Config (Right-click and Save As, make sure you remove the .txt extension)
Download and install Peace GUI
Once you run it, make sure it says "Yes, Installed" like below. Then you can click the Install button, say yes to the prompt, then click Start Peace
Uncheck "Check for a newer Peace version" and Check "Don't show this window at startup" and click the Full Interface
Inside of Peace, double-click the Steam Deck configuration in the bottom-left
This doesn't need to run at startup or anything. Reboot for all changes to take effect.
Lossless Scaling is an application that can upscale games(yes it has FSR as an option) and can be purchased directly on the Steam Store for $5 or less:
This app can fix the issues with certain situations for games, such as:
There are other options, such as MagPie or Borderless Gaming, but Lossless Scaling is cheap, works better(in my experience) and received updates often
Lossless Scaling is DRM Free and it can be copied outside the SteamApps folder(and then ran without Steam)
Here are some instructions to set it up:
Steam + D-PAD Up
Steam + D-Pad Up
Some games may function better in SteamOS thanks to Vulkan Shader-caching. However, Windows has the same capabilities. A couple things to note however is that it is not recommended for online games with anti-cheat as it could result in a ban due to the modification/addition to game files -- and it does not work for Gamepass games in testing.
You can set this up by following the YouTube guide here (highly recommend DXVK A-Sync):
The following mod will enable DLSS on certain games for the Steam Deck(or other AMD hardware). This has not been extensively tested, but you can view the compatibility list to see what games are supported:
That's it for the guide! Check out the last step 9. Troubleshooting Problems for fixes to common issues.