Currently 'doas' is missing in the drop down list of privilege escalation methods in credential. Since the method is already supported in core. It can be also added in AWX.

Should just need to add it here: https://github.com/ansible/awx/blob/devel/awx/main/constants.py#L16-L18
Potential unit tests here: https://github.com/ansible/awx/blob/devel/awx/main/tests/functional/test_credential.py
This will be resolved soon via a downstream change.