end_play and end_host are similar, but not exactly the same.

• end_play will end a play for all hosts
• end_host will end a play for certain hosts

end_play and ansible.builtin.fail are also similar, but not exactly the same.

• end_play will end the play for all hosts and will consider the play "failed"
• ansible.builtin.fail will end the play for certain hosts and will NOT consider the play "failed" (this article)

For example, let's say you have the following playbook which uses ansible.builtin.fail.

---
- hosts: all
  tasks:
  - ansible.builtin.debug:
      msg: Hello World
  - name: fail the play for server2
    ansible.builtin.fail:
      msg: failing the play
    when: inventory_hostname == 'server2'
...

And you run this playbook using this command, which runs the playbook against server1, server2 and server3.

ansible-playbook example.yml -i server1,server2,server3

Running this playbook will output the following, where the play was considered failed for only server2.

TASK [ansible.builtin.debug]
ok: [server1] => {
    "msg": "Hello World"
}
ok: [server2] => {
    "msg": "Hello World"
}
ok: [server3] => {
    "msg": "Hello World"
}
TASK [fail the play for server2]
skipping: [server1]
fatal: [server2]: FAILED! => {"changed": false, "msg": "failing the play"}
skipping: [server3]
PLAY RECAP 
server1 : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
server2 : ok=2    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
server3 : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

On the other hand, let's say you have the following playbook which uses meta: end_host.

---
- hosts: all
  tasks:
  - ansible.builtin.debug:
      msg: Hello World
  - name: end the play for server2
    meta: end_host
    when: inventory_hostname == 'server2'
...

And you run this playbook using this command, which runs the playbook against server1, server2 and server3.

ansible-playbook example.yml -i server1,server2,server3

Running this playbook should return the following, where the play was ended for only server2 but not considered failed.

TASK [ansible.builtin.debug]
ok: [server1] => {
    "msg": "Hello World"
}
ok: [server2] => {
    "msg": "Hello World"
}
ok: [server3] => {
    "msg": "Hello World"
}
TASK [end the play for server2]
skipping: [server1]
ok: [server2]
skipping: [server3]
PLAY RECAP 
server1 : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
server2 : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
server3 : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

And let's say you have the following playbook which uses meta: end_play.

---
- hosts: all
  tasks:
  - ansible.builtin.debug:
      msg: Hello World
  - name: ending the play for all hosts
    meta: end_play
...

And you run this playbook using this command, which runs the playbook against server1, server2 and server3.

ansible-playbook example.yml -i server1,server2,server3

Running this playbook will output the following, where the play was ended for all hosts.

TASK [ansible.builtin.debug]
ok: [server1] => {
    "msg": "Hello World"
}
ok: [server2] => {
    "msg": "Hello World"
}
ok: [server3] => {
    "msg": "Hello World"
}
TASK [ending the play for all hosts]
PLAY RECAP
server1 : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
server2 : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
server3 : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0