Not sure what you're trying to say but

Van gogh's tdp range is 4-15W

Z1e's tdp is 9-30W

Since these are amd's marketing tdp numbers, the actual limit would be 35% higher at 20W for van gogh and 40W for Z1e. Both handhelds have 40000Wh batteries and steam deck already dips below 1.5 hours with some games.

Sure, if people continue to play their games at 800x1280x60 on the rog ally it will last longer but if they try utilizing the better screen and faster apu it will have much worse battery life.

Whenever one of these handhelds pops up the main selling point is always "more powerful than the steam deck!" or "steam deck is only 720p 60hz!" But no one seems to understand that valve picked that specific hardware for a reason. The 720p screen uses less power and the APU doesn't have to push a 1080p panel on a handheld meaning more battery life, the APU at the time was probably the most power efficient for the performance so the battery doesn't last for only an hour, it last for 4 or 5 (not sure on exact numbers). The ROG ally is probably going to run very hot compared to the steam deck, but that's speculation on my part. Valve is full of smart individuals, they didn't pick the hardware they did on a whim, that's where the difference is going to show between these devices and the steam deck.