Hello all! I wanted to briefly share my experience modding my Steam Deck OLED, should it be of use for anyone else!
It seems like most replacement button sets are fully compatible with the Steam Deck OLED, except for the triggers/shoulder buttons and replacement trackpad covers. The shells are compatible but I did not want to remove my screen + adhesive to do the front shell, so I just did the back. I did have to trim the silicone piece that the volume buttons connect to to get it to fit.
The gulikit hall effect joysticks that specifically mention Steam Deck OLED compatibility were easy to install and calibrate by running thumbstick_cal in desktop mode, and whether it is just placebo or not, they definitely feel more precise than stock!
I did not do extensive before/after thermal testing, since many people have done that before. I did repaste the APU with Thermal Grizzly Kryonaut Extreme as well since I had to remove the heatsink to get access to replace the power button
Here are the products I used: