How can I have unlimited keyboard shortcuts?
I don't believe that macOS will let you add key sequences in System Preference -> Keyboard -> Shortcuts. However, you should be able to do it, but you will most likely have to manually add shortcuts in plist files.

I think the answer provided here, as well as this repository, will help you create custom keyboard shortcuts.

You can also check out Keyboard Maestro's FAQ on their workarounds to key sequence shortcuts.