Hello, Ubuntu Studio/KDE here.
Is there any way to change the shortcuts priority? For example, there is a way to switch to keyboard layout 1 by pressing left Ctrl, and to layout 2 by pressing right Ctrl, but in that case any other shortcut that has Ctrl stops working. If I set the layout switching to Ctrl+Shift, any shortcut using Ctrl+Shift+anything else won’t work.
On windows, there is a third-party program that allows selecting layouts via right and left Ctrl, and it doesn’t interfere with any shortcuts that use Ctrl, i.e. the layout change will trigger only with a single Ctrl press, no holding, no chords. Is there a (relatively easy) way to achieve this in Linux?


Not so; if the action is bound to the key release, you can still use Ctrl as a modifier with other keys.
FWIW I use Windows key combos for most shortcuts; they never interfer with canonical shortcuts (like Ctrl-c, Alt-F4 etc.).