Co-authoring for labelled files with Apps for Business

Hello Community.
A client of mine wants to protect his documents with Purview. The licence used is Microsoft 365 Business Premium. Now there is a requirement that can't seem to be solved after studying the docs. Before I test this and make basic settings, however, I am interested in whether one of you can make a statement about this.

The customer would like to continue using AutoSave. For this, co-authoring must be activated for encrypted files. However, the requirement is "Apps for Enterprise" (https://learn.microsoft.com/en-us/purview/sensitivity-labels-coauthoring#prerequisites). The customer does not have this. Does this really not work with Apps for Business? Do any of you have experience?

Thank you in advance.
Greetings Joerg