Metadata for Users

Airtable support seem to be struggling with what I assumed was quite a common use case. So trying here:

Right now we have an employee database, each employee name is a record in the primary field. We also have other data in that table, like email address etc.

We have a deliverables (think, tasks) table which we use to set deliverables for customers and each deliverable has an owner, we link to the employee table to deonte that owner and as such we can pull in other info (like email address) into the table via a lookup.

We want to move away from adding the employee as a linked record and just add the ‘user’ (the airtable defined field of user) since they are one and the same thing (and employee is also a user).

I’m struggling though with how to then have a table of info to do with that user I can pull in, seeing as a user can’t be a primary field so I can’t link to it in another table.

any help or advice for a workaround much appreciated!