Associating documents to Project Server Tasks

Our organization recently migrated from SharePoint/Project Server 2010 to 2016.  In 2010, there was a way (rather clunky) to associate documents in a Project library on the Project's SharePoint site to individual Tasks within the Project, along with Risks and Issues.  In SP 2013/2016, the method of association was changed for Issues and Risks, to used Related Items to create associations with the Project-mirrored Tasks list on the site, but the Documents association functionality was removed entirely.  If you try to use Related Items to link Documents to the Tasks list, Publishing the Project plan will result in errors on the sync.  We are using SharePoint/Project Server 2016 on-premise.  Has anyone developed a method of creating a 2-way association of Documents and Project Tasks/Task list or otherwise?  We have a need for users to provide supporting information to management as to the status of their tasks.