Method #1
Click the link https://myaccount.google.com/.Check in the upper-right corner that the account is exactly the one we are logging into. If not, then switch to the appropriate one.
Just go to the «Security» → «Your devices» → «Device management», then untie all mobile devices as in this guide.
Do the same with text messages from your phone. Sometimes it turns out to bypass through https://myaccount.google.com/ and untie the phone. If after that it still requests a text message from the same number, then you need to wait for 24 hours.