I clear my throat. Do it loud enough that the other end can tell someone is on the line, so they'll know to start the conversation. It isn't a rude "WHAT" type answer, but it doesn't directly acknowledge the caller, and is not inviting a conversation. Its a common enough act that it's not suspicious nor weird to hear during a conversation, and therefore its not off-putting if extended family or clients called from an unknown number.

It doesn't share my voice (for fingerprinting, demographic leak, etc, smh).

Also works as a bot filter - Humans tend to start with a "hello..?" because they're not sure anyone is there, while robots use the non-zero audio as a signal to start talking with full confidence.