Most handhelds are designed to be used portably, so I don't know why anyone would want that.
Isn't handheld = portable ?
Also, since you want it for streaming via Moonlight, you could use any Android device. If you find one with a removable battery, then you'll get exactly what you're looking for. You only need a telescopic joystick if you are aiming for a Steam Deck / Switch form factor.
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