Do we have any articles in appian to support read only access to prod ( both DB and designer) for developers to triage prod issues?

You are on the right track with your thinking. It does depend on what your support policies say as well so consider that. If you have a privileged access policy, then there may be another system that grants access and moves the users in to an AD group that then maps to a set of "read only" groups linked to the app objects. 

If this is just linked to Appian, so no AD / SSO integration, then you can do a similar thing and grant users access via a process and then move them to a group that denies them access to objects when the task has been completed. The key thing is auditing who has access etc.

I am designing our support process like this: https://appian.rocks/2023/09/20/support-processes-on-appian/