Passive income and Segurança Social obbligations (for not employed and / or self-employed)

Hi all

I have currently NHR status and I am also self-employed (simplified regime).

I have some foreign passive incomes (tax free under NHR) and I am planning in few years to only live of passive income and stop my self-employed activity in Portugal.

Once I will terminate my self-employed activity will I still be required to pay some minimum amount to social security and therefore remain insured for old age, disability and survivors’ benefits? or I will not be required to pay anything to SS (but of course will lose right to the mentioned social insurances)?

If any feedback from anyone that is in this situation (and EU citizen in work age) would be very appreciated.

Thank you in advance