FIRST of all, The Most Important Feature of Kicad is the Shortcuts/Hotkeys
But it is being a bit frustrating using Kicad 7 recently. All the good stuff is messed up.
Some important shortcuts are broken.
Special care should be given to the Symbol and Footprint editor.
For instance, I cannot use Ctrl+s to save on the Footprint editor anymore.
When I hold Ctrl, the mouse pointer changes to something like “arrow up”. And this may be preventing Ctrl+s to work.
For me, on 7.0.4 on fedora 37 (Linux), in the footprint editor, the mouse pointer changes, but Ctrl+S still works for saving the footprint, as does Ctrl+Shift+S for “save as”.
In the symbol editor Ctrl+S doesn’t do anything when I have opened a KiCad library symbol, perhaps because the KiCad default libraries are read-only, but Ctrl+Shift+S does work. If I press Ctrl+S on a symbol from a user library, it does save the changes made.
For me it works in both english and swedish language, with swedish keyboard / locale.
The OP might have another language / keyboard / locale of course.
But I suspect that he might potentially also think it doesn’t work because Ctrl+S doesn’t do anything in the symbol editor if the library is read-only.
There are moments when shortcuts do not work. I could not identify those moments yet to describe them here, but sometimes shortcuts do not work as intended.
In the footprint/symbol editor it partly depends which part of the GUI controls the input focus:
last clicked on main canvas → the main window controls focus (most hotkeys work)
last clicked on library tree pn the left: → library tree controls focus (you can navigate with cursor keys in this pane) → hotkeys not working
A similar behaviour was introduced with the new properties panel+search panel in the board editor.
There were already discussion on that topic on gitlab and some hotkey-related issues are still open. Also there were different expectations from different users - some expected the hotkeys to work even the tool-panes control the focus, some prefer that the hotkeys only work in main canvas.