Effective Strategies for Managing Metadata Across SharePoint Libraries when updating column value

Hello SharePoint Community,

I've recently implemented SharePoint as our department's record management system for projects. Within our project SharePoint site, various documents and items in the site library and list contain essential metadata such as "project manager" and "project name."

At the end of the year, we plan to archive these project documents and items in a designated archive library and list. As part of this process, we also intend to update the "project name" column with the list of projects for the upcoming year.

To ensure we don't miss any crucial metadata information in the files during this transition, what considerations should we take into account? My main concern is that we won't be able to add to the "Project Name" column every year and need to keep it updated with the "Active Projects" list.

So, what will happen to the archived project documents that contain the "project name" metadata when its value is not in the "Project Name" column anymore? What would be the best solution to prevent the loss of metadata in this archival process?

Looking forward to your insights and expertise.

Thank you!