You can get something that performs notably better (in terms of CPU and GPU), but only at a significantly higher price, and the higher performance will only really be achieved at a higher power consumption level.
IMHO there's no real competitor for the 569€ OLED Deck -- especially as a complete package, taking into account performance, battery life, screen, audio, input, ergonomics, software and pricing -- unless you have very specific requirements (primarily, really wanting to play multiplayer games with incompatible anti-cheat).