I agree with some of your points. I say only some because I haven't tried to connect it to a TV or monitor. I strictly use it for on-the-go or couch gaming. I like the extra power compared to my Steam Deck but my issues...
Windows - SteamOS is just amazing for a handheld device compared to windows hands down, no argument. However it is nice that I can play everything and anything I own across Epic, GOG, Steam etc without having to hack.
Ergonomics - It just doesn't feel great in my hands compared to my Steam Deck. It fatigues my hands after a 2-3 hour session.
Battery Life - You nailed this one. Not much else to say.
I still think it's a great device and would recommend it for anyone looking to play any PC game they have in their library without worrying about compatibility.