The declaration below
  abc: "/{{ xyz.split('/')[1:3]|join('/') }}"
gives what you want
  abc: /u01/dbbackup_nfs
Q: "I needed from the first slash(/), so made it xyz.split('/')[0:3]|join('/')"
A: This depends on whether the path is absolute or relative. You can use a condition if you're not sure
  abc: |
    {% if xyz[0] == '/' %}
    /{{ xyz.split('/')[1:3]|join('/') }}
    {% else %}
    /{{ xyz.split('/')[0:2]|join('/') }}
    {% endif %}
The playbook for testing
- hosts: localhost
  vars:
    abc: |
      {% if xyz[0] == '/' %}
      /{{ xyz.split('/')[1:3]|join('/') }}
      {% else %}
      /{{ xyz.split('/')[0:2]|join('/') }}
      {% endif %}
  tasks:
    - debug:
        msg: "{{ xyz.split('/')|to_yaml }}"
      vars:
        xyz: "u01/dbbackup_nfs/orabackups/odaserver-c/database/857970682/akash_2/db"
    - debug:
        msg: "{{ xyz.split('/')|to_yaml }}"
      vars:
        xyz: "/u01/dbbackup_nfs/orabackups/odaserver-c/database/857970682/akash_2/db"
    - debug:
        var: abc
      vars:
        xyz: "u01/dbbackup_nfs/orabackups/odaserver-c/database/857970682/akash_2/db"
    - debug:
        var: abc
      vars:
        xyz: "/u01/dbbackup_nfs/orabackups/odaserver-c/database/857970682/akash_2/db"
gives
LAY [localhost] ******************************************************************************
TASK [debug] **********************************************************************************
ok: [localhost] => 
  msg: |-
    [u01, dbbackup_nfs, orabackups, odaserver-c, database, '857970682', akash_2, db]
TASK [debug] **********************************************************************************
ok: [localhost] => 
  msg: |-
    ['', u01, dbbackup_nfs, orabackups, odaserver-c, database, '857970682', akash_2, db]
TASK [debug] **********************************************************************************
ok: [localhost] => 
  abc: |-
    /u01/dbbackup_nfs
TASK [debug] **********************************************************************************
ok: [localhost] => 
  abc: |-
    /u01/dbbackup_nfs
PLAY RECAP ************************************************************************************
localhost: ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0