There are plenty of supposed Steam Deck killers available in the portable gaming space, from the Asus ROG Ally to the Lenovo Legion Go and all the Ayaneo and ONEXPLAYER devices in between. But none of them have managed to outright slay the dragon that is the mighty Steam Deck yet.
You may want to look into that… mine sleeps for a day or two at least typically.
I don’t play mine every day or even every week. The last time I turned it on was last Monday. I just checked and it’s exactly where I left off and at 6%. I have no idea how much battery I had when I put it into sleep mode, but it was likely full or pretty close.