Hi guys,
I’m currently working on an MCP Server (AI) that does exactly that: move thousands of upladed files from one table to another.
This is necessary due to fix a poor early design decision from a client.
This tool also enables the creation of a low-records sandbox for those who need to experiment on a copy of their app, without the fear of braking anything, but who can’t afford the luxury of copying the whole app including the records.
For more details, see my post here: 
Moving around thousands of uploaded files in 55 minutes !? - API & Custom Code / Show & Tell - Knack Community Forum
Let me know if that sounds interesting,
Norm