@Ml111674
This is always a challenge when changing the phone number used in 2-step verification.
Google Nest says:
"If you plan to get a new phone number and stop using your old one, you should turn off 2-step verification before you deactivate your old line. Then you can turn 2- step notification back on with your new number.
Important: You’ll need to enter a verification code from your old phone number one last time. This is a security precaution to confirm your identity and help protect your account."
Under "If you can't access your phone number or email where we sent the verification code to", they go on to say:
"1. Contact your phone or email service provider’s support for help regaining access to your phone number or email account. For instance, if you can’t remember your email account’s password, you should be able to reset the password on your email provider’s website and then access your email account to view the email we sent to you.
2. If you can’t regain access to your phone number or email after contacting their support, you’ll have to factory reset your Nest products, and then add them to a new account. Note: You’ll have to re-invite people to share access to your home in your new account, and you’ll lose any video history and device settings information."
https://support.google.com/googlenest/answer/9295081?hl=en#zippy=%2Cchange-your-phone-number
I suppose you could try contacting Support starting with the link below to see if they have any other recourse at all:
https://support.google.com/googlenest/gethelp
