1. This is
not OxygenOS. I wouldn't say it's complete crap but it's leaves a lot to be desired.
2. Battery life is poor.
3. Camera is barely any better than for my even older than yours OnePlus.
4. Yeah, it's fast, too bad it's overheating even when using light apps like Google Maps.
I've no idea what to upgrade to but I'm not a fan of OnePlus 11 by a long shot. I've heard some Lenovo/Motorola and Asus phones feature a ROM which is close to stock Android.
Oh, and the Pixel 7 Pro is certainly an option as well, though stock Google Android is missing a ton of features from OxygenOS, even simple ones such as double tap to wake (it can be single tapped to wake but that leads to an extreme number of unnecessary wake up's).