Well, I'm glad I don't use GA on my personal site, then, even if it means I have no idea what traffic levels it gets. GA is incredibly popular though - I would guess the vast majority of blogs etc. use it and have no consent to do so.
Anonymization (if you actually believe Google despite their conflict of interest and previous GDPR breaches) still happens on their server, so the IP address (which counts as personal data) is still transmitted there.
I guess you may actually make it truly anonymous from a GDPR point of view if you proxy all calls through your own server and strip out anything that can be used to reidentify a user - so no IP addresses, session IDs, etc.