Help connecting to a custom list within Project Workspaces in Project Web Application

I need help figuring out how to connect to a custom list within each project workspace in my organization's Project Web App using PBI Desktop. I can connect to more general project data via OData feed, but I can't find the custom list I need within that data.

Just in case this is somehow related to the issue I'm having - I've also tried to connect to an individual custom list associated with a particular project via Sharepoint List/Online List and Sharepoint Folder (ex. URL: https://<tenant name>.sharepoint.com/sites/pwa/<project name>/Lists/<Custom List name>) But, I receive the following error in each case - 

Any ideas/guidance for how to connect to a custom list within a Project Workspace in Project Web App would be greatly appreciated!