I see that in Azure Devops the billing account is set per organization. So, I can do a cost analysis per organization. Is it possible to do the same thing on a project level with labels and etc? I have checked but I couldn't find any labeling for the projects.
I want to see what is the exact cost of each project based on users, pipelines, parallel jobs costs.
I could not find any billing per project as your question states.
As an alternative or workaround ( I'm not saying this is an ideal solution) you could separate your projects in organizations in order to be able to bill them separately. Just in case here is the link about billing per organization and here is the link for Billing overview for Azure DevOps in case it may give you some more insights.