Files lost during migration

I migrated our vault from one server to another by moving the file data and the database backup.

But the first time, I moved them on different dates and had to do it again to have the same information moved across.

The second time, only the database was moved to the other server by mistake.

When I did the cutover this week, I used the one time-export to grab the differences between the second time and the cutover day.

So, between the second time I moved and the time I ran the one-time export, there were files missing in the new file data location.

My situation is that I need to grab these missing files from this period on the old environment and add them to the new environment without losing the work they've done in the last few days.

I tried to do the one-time export in the new environment with the changes made in these few days, but as they updated the metadata from missing files, the export failed.

Is there a way to fix this?