In August 2023 free monitoring was decommissioned. Along with this, option cloud.monitoring.free has been removed in MongoDB version 7.0.

This should be documented in Compatibility Changes in MongoDB 7.0

I was using
 

cloud:
  monitoring:
    free:
      state: off 

in my configuration but after upgrade to MongoDB version 7.0 the mongod service did not start anymore.

Kind Regards
Wernfried