This is so useful. a Gmail account is so much more than just an email account at this point. my first gmail account was made when anonymity and cool email was more of trend than your actual name - so i based upon my favorite book in 2006. 20 years later the account is tied to my oft used primary google voice number so lingers even with obscure and hard to spell email.
i could gave moved my google voice number, but it seems like a convoluted process and have had my number since about Grand Central acquisition.
in my experience, in/out porting with google is super quick and works great. It costs $20.00 IIRC. I port my primary phone number around to avoid unlawful surveillance, handy tool in the bag.