I used to do business advising from an interdimensional perspective from the '90s to about 4 years ago.

There's no easy way around this. You've listed many good alternatives / solutions some of which I've advised.

Ghosting is a horrible brick wall and immature at best.

I found that conditional trust, holding something back (as in creating a small secret or mystery) without any dishonesty is a good negotiating tactic in keeping interest in a possible deal/contract. This could include politely dividing your attention during your call, note, text, or email.

It's an energetic thing. If all your energy is on the exchange right out of the gate then you could be viewed as desperate or needy. This gives the other party any upper hand to dismiss or be apathetic. Trust must be earned, be friendly, but don't let yourself go... Maybe you know this already?