Google is silently linking phone numbers across accounts — the privacy risks and how to stop them
(www.androidauthority.com)
I've been doing this for about a year now and have run into no issues with the numbers I transfer from carriers. more and more the pure VOIP numbers are not working.
I won't go into recommending any, for reasons I describe in another comment in this thread. I will however not recommend VoIP.ms, they wanted me to do a facial scan and when I refused completely blocked access to my account with no appeal.