Huh this is a great idea 🤔
“In episode 141 (Oct 2019)  of his Security, Privacy and OSINT podcast, Michael Bazzell told of how he gets a phone number for a week for $2.50. He buys two pre-paid Mint Mobile SIM cards for $5 on Amazon . Each comes with a one week free, limited trial. He uses them to setup assorted social media accounts. Once setup, converting the accounts to 2FA means never needing the phone number again.”
Personal instance of nitrohorse (nitrohorse.com).