Cloudflare is also questionable when it come to GDPR. Lots of folks conflate privacy and cookies with GDPR. Compliance is much more than that.
One could argue that since it's a US-based company it can't be Shrems II compliant, but you can make that argument about a lot of things.
You might have a legitimate interest in processing the IP, but because of the aforementioned issues, you cannot provide sufficient controls nor protection of Personal Data.
As such, using Cloudflare as your Data Processor, exposes You, the Data Controller, to DPA scrutiny. As always with GDPR/DPA and EU, whether it is illegal/non-compliant depends on each DPA.
https://medium.com/@christhaefner/shopify-illegal-in-germany...