Setup Read Only JDE ID / Datasource Override not working for user profile

Hello,

I am trying to setup a Read Only JDE environment where it reads some data from a shared data source that is used by 2 environments and some data from a data source that has archive tables (OCM Override). I have created a Database user with Select only access and added that DB user as a system user in JDE. In P98LPSEC, I have created a Data Source override and used the Read DB id. However, when I login to JDE, it uses the default system user "JDE" which has both Read and Write access.

Any Idea why this setup does not work ? Can you suggest any other options.. Those suggesting that I can use Action security with all buttons disabled do not consider batch programs that can update data. In a worse case scenario, I was thinking of using a dedicated data source instead of shared with JDE system user having Read only access to the tables.