I think one of my Google accounts is being attacked because without my desire
G-XXX codes are being sent to my phone via SMS. I want to know which email is this code for and want to inform Google for further assistance. how should I reach google and ask them these?
According to catzrule answer to "Suspicious "Unusual Activity" text - if spam, where should I report?"
Text (sms) is not something that Google could help with. Maybe your phone company?
Certainly sounds like a phishing attempt; others may correct me here.
Many sms clients on phones have a "block" feature. Long press on the message and see if you have that option.
That post is from 2016. If you want to make your own post go to https://productforums.google.com/forum/#!forum/gmail
In either case, it worth to check if you have in place all the security measures suggested by Google on Secure an account that has suspicious activity