I can't set keyboards shortcuts

i go to settings → keyboard → keyboard shortcuts → view and customize shortcuts → typing → switch to new input source (for switching languages shortcut)
but when it’s says “enter new shortcut to change [shortcut name]” it only detects few keys, i want to change it to shift+alt like on windows but it’s not detecting this, it’s also not detecting normal letters, some of the keypads it do detect and also the “`” key and “/” and keys like that but that’s it
what should i do

Yes, shift+alt dosen’t work, but i.e. shift+alt+a does.
Probably there are some limitations in usable keys and combinations.

Added gnome

there is any way to do shift + alt any way
because doing shift + alt + L is different for a such needed common action in windows and it would be great it i just continue to do that
from what i understand it’s linux so customization should be one of the main focus of the features, so i suspect it does possible some way
otherwise thank you