Minecraft Re-Console + Bliss on Steam Deck OLED
Did a quick test with the Re-Console 2.7.0 modpack and Bliss 2.1.1 shaderpack for Minecraft Java Edition 1.21.5 with Fabric 0.16.14 on Steam Deck OLED. You can see the refresh rate (FPS) on the top left corner of the screen whenever the debug overlay is shown. I'd say it's playable even with shaders on.
The world seen in this recording is the TU46 tutorial world from the legacy console editions of Minecraft, developed by 4J Studios.
Music: C418 - Clark