I think you don't understand the GDPR. The GDPR does not disallow the processing of personal data, nor does it disallow the sharing of personal data with suppliers or other entities in the supply chain. For example, if you run a merch store, it's perfectly OK to share the buyer's address with DHL or whoever does the shipping.

What the GDPR requires is that the user is informed about the processing and the suppliers used, and in some cases, provides consent to the processing.

The new proposal which suggests that pseudonymized data is not always PII is a different thing. It actually opens the door to a lot of new problems in my opinion. For example, with this new interpretation, big tech might question whether IP addresses are still personal data (which is something EU top courts had previously established)? What about cryptographically hashed values of your social security number (easy to break)?