rlb

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-alessia-pacella
  namespace: mongo-db
subjects:
  - kind: User
    name: alessia.pacella
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io
You can create similar RoleBinding resources for the other users:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-m-iadarola
  namespace: mongo-db
subjects:
  - kind: User
    name: m.iadarola
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-giuseppe-zuccarello
  namespace: mongo-db
subjects:
  - kind: User
    name: giuseppe.zuccarello
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-miriam-di-giulio
  namespace: mongo-db
subjects:
  - kind: User
    name: miriam.di.giulio
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-f-a-moccia
  namespace: mongo-db
subjects:
  - kind: User
    name: f.a.moccia
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin-rolebinding-sergio-pisciottano
  namespace: mongo-db
subjects:
  - kind: User
    name: sergio.pisciottano
    apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: mongo-db-admin
  apiGroup: rbac.authorization.k8s.io