Caps Key as a combination key?

I can address the caps lock key (or tabulator) already, but only on its own. As this key hasn't any function on my system outside of text edit/ pages, I'd like to use it for more, as it is free and so close to my left fingers, which are 90% on the left keyboard side.

Can I (already) use caps lock key + W, caps key + F1, caps key + Spacebar, option + caps key? ...

you can change it to right ctrl in system settings => keyboard => keyboard shortcuts, then you can use it with the "differentiate left/right modifier keys" option in BTT: