How can I transfer an Azure DevOps project from one organization to another?

In my DevOps organization, I've created a project for a client with git repo assets, boards, pipelines, etc. I'd like to transfer the project ownership from my organization to my client's organization.

How can I do this?

It's easy enough to switch ownership for the entire organization under "Organization Settings." But that's not what I want. I am looking, however, for that same workflow (if it exists) for a single project. The project ultimately needs to show up in their Organization space instead of mine.

If this isn't as simple as switching organizational ownership, is the save data an option?

I read here that I can save project data. But, there are no instructions on re-importing that data elsewhere. Also, I get the impression that I'm not getting a full project.

After the project is transferred they need to be able to continue to use it as it functioned in my organizational space.

I feel this thread with this answer is relevant

There is no official document to support this function.

We can use this extension OpsHub Visual Studio Online Migration Utility to migrate source code, work items.

In addition, there are Copy or clone work items and move git repositories between team projects features.

Seems worth mentioning that, in addition to the above, AzDO Boards migration tools lists:

Azure DevOps Migration Tools [marketplace link] as an expert tooling option.

StackExchange DevOps Q#15381, answer score: 2