It’s not blurry. It looks pretty decent actually. I don’t have any upscaling on and just play at 25-30 fps no issues. It’s not a game that needs the best fps to play

Also it’s probably blurry because you might not have set the correct resolution in gaming mode? Select BG, go properties and change the resolution from default to whatever you want. Just be warned that anything above 1080 will hinder the performance more

OK after sleeping, I realized what your issue probably is.

So by default, in the Steam Properties for a game, the resolution is set to “Default”. So when you plug it in to and display on an external monitor like a 1080p one, it uses the closest appropriate resolution to the steam deck’s display (1280x800) but with the new ratio (which is 16:9, as your external display). This is 1280x720; ie. 720p.

What will happen then is the Steam Deck will use the built-in OS scaling method, to upscale this from 720p to 1080p. In your side performance menu (the button with the “…”), you can set this to FSR with a Sharpness of about 2 to make it looks better. The issue with this method is that everything is using upscaling, including the UI; which makes everything a bit blurry.

But you can also instead do it another way, which is to force the game to launch at 1080p, and use the in-game FSR2 so that only the 3d game engine will use upscaling and the UI will be sharper.

• In Steam Properties, set the Resolution selection to “Native”; this will launch the game and allow for it to see the native resolution of the display you’re using, whatever that is (Steam Deck or the external one).
• After Launching Baldur’s Gate 3, go into the game settings, use Windowed Fullscreen (this will use whatever resolution the full screen window is at; so 1280 on your steam deck and 1920 on your external display), and then set FSR2 to ON with Performance or Quality setting. Also put the Sharpness Slider about 80%.

So the above setting should run the game in a manner where the UI looks sharp, and you still get performance similar to when you run it on your steam deck native screen.

There isn’ta docked mode. The system run at full speed of whatever max settings you have at all times.