I'll provide legacy battery icon setting. You won't get this option though on native taskbar though, so time to love it. Can't say anything about smart charging, Surface battery needs to be degraded first for it to be enabled it seems.
I'm not sure what SAB jump lists lack? What's different with Default + sharp corners from Win10? Native jump lists can't come back.
There isn't (it won't be optional in Win11 either).
If you want custom app shortcuts to be searched as Programs but for some reason you don't want them in All Programs, you can create them in folders in
%APPDATA%\Microsoft\Internet Explorer\Quick Launch\User Pinned
Then add those custom folders to SAB right pane