Ah, I see. I allready thought that this would be redundant. But I think I try it the other way round: Add an additional Admin visible only profile field to the user profile via the hook edit_user profile, outside of the acf scope to assign the id of the cpt to the user.
I allready use a self coded frontend login/register process plugin that has hooks inside the edit form and the update user process, should be the right ones to display the additional user editable fields via acf_form nd to update the cpt fields.
I will post my progress soon hopefully 😉 Thank you for your help so far.
