That's kind of the nature of this sort of apps. Instead of implementing the clipboard handler yourself, you just rely on whatever clipboard utility the system already has.

Most terminal emulators will copy with Ctrl+Shift+c. I'm using foot, if you set this part of your config, it will copy with just Ctrl+c.

[key-bindings]
clipboard-copy=Control+c XF86Copy

But now for most shells you don't have a keybind to send SIGINT, which is very commonly used.