It’s possible I have to RTFM.
I checked the Bazzite documentation for the Ally and it says SimpleDeckyTDP provides more features than HHD so I didn’t experiment with it at all. I prefer using the Decky plugin mainly because it fits with the Bazzite theme better :P
IMO the only advantages the ROG Ally has over the Steam Deck OLED are
In every other way, the Steam Deck is superior (interface polish, battery life, HDR, touchpad).