You run a merch store. You want to share with your suppliers order data so that you can get the right number of sizes/colors/etc. Is this PII under GDPR rules? Technically, yes! Not only is there information on gender, but also people's height and weight and maybe even family makeup. Does it make sense to call this data sub-processing? Eh? Maybe? (To my knowledge, I don't know if any examples like this actually caught any enforcement.)
Under the new proposal, sharing this data is okay, so long as you use pseudo-anonymous identifiers (customer-1234, customer-1235). You still can't share sensitive identifiers (name, address, email, login, etc).
Obviously the elephant in the room is AI and training data. But this also simplifies a lot of the ticky-tacky areas in GDPR where PII rules are opaque and not-consistently enforced anyway.