I recently started work with a consulting company and was tasked with "optimizing" their on-premise SharePoint 2013.
The problem is that SharePoint was their replacement for a massive fileshare with non-uniform folder structures that sometimes go up to 10 levels deep and each contain different files with sometimes completely non-descript names.
Their current solution is to have a subsite for each project with multiple document libraries that contain nested folders to mirror the old fileshare structure.
Files that are placed in this structure have 6 managed metadata tags, 3 of which are mandatory, that have up to 50 options which are completely seperate from the folder structure and may repeat itself (same tags for different fields).
People access the libraries through the explorer like the original fileshare and sometimes refuse to use SharePoint for saving files because each time they have to assign multiple tags to the files but without the tags people would not even find what they are searching for (except when people assign random tags just because they have to)
I plan to upgrade to SharePoint 2019 sometime in the next 18 months.
How should I go about breaking up this abomination of a file structure while providing usability, manageability and a positive user experience?