How I Got a Truly Anonymous Signal Account
https://theintercept.com/2024/07/16/signal-app-privacy-phone-number
Yes, you can use Signal without sharing your personal phone number. Here’s how I did it.
Doesn't seem especially practical, but I thought folks here might be interested in this method. With the increasing scarcity of pay phones I suspect it might be equally as "easy" to get a burner cell phone with cash and register a signal account that way.