Using Ansible with sudo su

I’m trying to setup Ansible to access our infrastructure from and admin account. With not much success.

I need to login to our RedHat servers with my user “my_user”. then we need to switch to a admin user “sudo su - admin_user”

ssh my_user@server1.com (doesn't need a password)

From Server1.com

sudo su - admin_user (requires password)

thanks

--------- Tried ---------

→ Tried adding to playbook yaml file

---
- hosts: test
  become: true
  become_user: admin_user

→ Error fatal: [server1.com] => Missing become password

→ Tried adding to ansible.cfg file

[privilege_escalation]
become=True
become_method='sudo'
become_user='admin_user'
become_ask_pass=true

→ Error fatal: [server1.com] => Internal Error: this module does not support running commands via ‘sudo’

ansible works with either sudo or su, the 'sudo su' combo does not
work (also it is not needed, sudo can specify a user).