I had the original Steam Deck and the OLED Steam Deck and neither of them would hold a charge past a day or so. It's a constant annoyance for me as I don't want to leave it plugged in 24/7 but if I don't, it won't be ready to go when I use it. I often end up playing while plugged in which is just silly.
A week of battery (while it's "off") would be amazing, it feels like I can't get 24hrs without the battery being trash.
Compare this to my iPad or MBP and the difference is stark. I really only use my Switch in docked mode (the joycons suck) so I don't have a good read on how long it holds it's battery but I assume it must be better than the Steam Deck.