Sorry for the German only link, but this is from today and didn't make the rounds yet. It is not really about Shopify itself, but about the use of CDNs - which would be even more worrisome. Shopify Support couldn't help the shop owner.
GDPR core is pretty simple: You cannot do stuff (process, store, transfer to third parties) with PII unless X condition is met. An internet site, on first visit (being genuine first visit or just cookieless visit) cannot do things with PII, because there is just no way to even tell if X is met, therefore not only data storage (IP address in Apache access logs included) is illegal, but moreso transfer to third party v…
Keeping those IP logs for security reasons is also legal (assuming you keep them safe for an applicable amount of time)
Using that data for analysis is not legal.