How to set up focus mode to let calls through with no sound & no vibrate

I am struggling to set up a focus mode to work the way I want.

I want any calls that I receive not to ring, and not to vibrate.

At the same time, I don’t want the caller to get a busy tone, rejected tone, or out of cellular range tone.

Oftentimes the caller thinks that the call is not connecting and they try again. This allows them to break through due to ‘Allow Repeated Calls’ option being enabled.

I just want the caller to think that the call is ringing, and that I’m away from my phone.

What’s the best way to set this up? I’m finding Focus Modes to be generally quite clumsy and complicated.

Thanks for your help!