PSA: Your Steam Deck OLED May Have Audio Crackling Issues on the Headphone Jack

Insulating the screws on the audio PCB may provide a workaround.
Top Things To Do After Getting a Steam Deck OLED

Make your device even better with a few software tweaks!
Overclock Your GameCube Controller Adapter on Steam Deck

Finally, an easy way of doing it, and stays consistent across reboots too!
Turn Your Steam Deck OLED Into a Buttery-Smooth 120 Hz Machine With This Script

LCD models are also compatible with this script to run at 70 Hz.
No, You Can’t Upgrade the LCD Steam Deck with an OLED Panel

You can’t upgrade to the 50 Wh battery either.