f2 VS rename

An alternative solution would be to use a batch renaming tool like F2 and rename all the images based on desired variables from the existing metadata

If you want a "global" index your only choice is to rename "manually" using another tool to batch rename, that is also what I do in the moment, I just sort the files by date of creation and rename them using F2 https://github.com/ayoisaiah/f2, but you can also use Bulk Rename Utility or Advanced Renamer which is what I used to use while using windows.

250 would be no problem for the Advanced Renamer GUI. On the other hand, it really bogged down loading more than 2000 or so. And my memory was that the Advanced Renamer command-line version choked down quite badly on huge numbers of files. I wish I could remember how long the Bulk Rename Utility command-line operation took. It seemed quite reasonable to me; the critical thing for me was that I was able to process many thousands of renames in one unattended job, without having to break up the job into smaller chunks, with all the manual intervention involved. I didn't try to assign a particular number of cores for the operation. Also you might want to have a look at https://github.com/ayoisaiah/f2 .

F2 can rename based on a CSV file though if that helps

F2 is a cross-platform file renaming tool. I have to deal with a lot of incoming image files and it helps keep my file system sane.

F2 is a command-line batch renaming tool with built-in variables including date (easy to use and easy to revert if a mistake is made)

See if https://github.com/ayoisaiah/f2 helps (I haven't used it, just know about it)

I'm not sure if the labels are added to exported images, but you could then use F2 to rename the files in bulk

Read the documentation but you can use --max-depth 2 to limit it to two folders deep and use --only-dir to only rename folders

There's the awesome but difficult to google f2: https://github.com/ayoisaiah/f2 .