I am trying to find a way to list all the users setup as system administrator an

To find all system administrators, you can run the following expression:

=load(
local!designerUsers: getdistinctusers(getgroupbyname("Designers")),
local!adminUsers: apply(fn!isusersystemadministrator,local!designerUsers),
index(local!designerUsers,where(local!adminUsers),{})
)

The default Designers group contains all system admins by rule, but non-admin users can be added to the group so the second step is needed as a safeguard.

To find all system administrators, you can run the following expression:

=load(
local!designerUsers: getdistinctusers(getgroupbyname("Designers")),
local!adminUsers: apply(fn!isusersystemadministrator,local!designerUsers),
index(local!designerUsers,where(local!adminUsers),{})
)

The default Designers group contains all system admins by rule, but non-admin users can be added to the group so the second step is needed as a safeguard.