Using S1 form for health entitlement

I am confused by the health insurance requirements of the Residence registration process.
The Malta healthcare entitlement website states that you can register your S1 form with the Entitlement Unit once you have completed the residency registration process.

But, one of the requirements to register as for Economic Self Sufficient residence is health insurance.

So it seems to be a catch22. What is the correct order to navigate this process?
-@Pandorak

Don't know about Greek citizens but the UK also have another agreement in place called the Reciprocal Health Agreement which you can use by registering with the Maltese health authorities when you first arrive and then you can always submit the S1 later after Residence card issued. (S1 for UK citizens is only issued for those in receipt of UK State Pension)

Perhaps Greece has a similar agreement to the RHA.