Existing feature to start off with

As described here, a system administrator can can reset an Atlassian product on a cloud instance manually.

New feature proposal

Basic expectation

However, I would appreciate if there was the possibility to do such steps - reset/delete, reactivate host products - programmatically, i.e. via REST API calls.

Additional expectations

Eventually, I'd also welcome a new feature to even create and permanently delete cloud instances on behalf of another "master" instance (or its administrator).

As far as I know, permanently deleting an instance is currently possible by contacting the support team and personally submitting a dedicated request only.
The first step would be to allow for initiating this action on the System Administration / Apps Management UI. This would give full control over instance management for the system admin.
As a second step, these actions should be made available programmatically, too. In other words, custom Atlassian cloud sites (e.g. Jira or Confluence instances) should be dynamically created, configured ("factory reset", populated with initial data, etc.), operated and killed upon changing needs.

Instances cannot and should not be managed by another, random account, but permission should be granted for "friend" accounts. This is what I meant with the master-slave analogy. Technically speaking, a master account (cloud instance owner) should be able to create new, temporary test instances on subdomains, without interfering the global Atlassian ecosystem.
As the resources are finite, of course, I would understand if there were some limits defined for each account, how many of such test/temporary environments could be in use in parallel (they could use a sort of cloud instance pool). On the other hand, if the life-cycle management of such test instances would be kept under control of the system admin (or some custom-developed app, which does this management in place of the admin), this would be a powerful feature, anyway.

Background, rationale

Just to provide some reasoning to my request, in order to effectively configure and use/reuse cloud environments for testing purposes upon emerging needs (e.g. to test an addon built from a spcific branch), cloud instances and installed host products should be managed programmatically.
For the time being, the only possibility is to request a private developer/test instance, configure it manually and deploy/debug/test your apps on there. I would be grateful, if all this fiddling could be replaced some company-wide, transparent, for everyone accessible (I mean, shareable with all team members) mechanism.