Thanks for your thoughts, Max.
Unfortunately I'm snowed under with the work that puts food on my table, so I'm unlikely to be able to do anything with these ideas for a little while.
However, if you're using
NAS-preferred filenames, you can specify the correct date in the filename. The regular upload process will warn you if the filename date and EXIF date don't match (although, in your case, there's no EXIF so it should just take the filename date. Note that the date is formatted YYYYMMDD. Fast-track upload should assume that you know what you're doing and just accept the filename date (although it's been a while since I wrote that...).
I use Canon Digital Photo Studio to batch-convert from raw to TIF for editing, and have that generate filenames like _EFHK_20200624_(number).tif - then prepend the reg when I save the final JPEG for uploading. That's the quickest way I've found to name files in a way that works.
My friend and I applied for airline jobs in Australia, but they didn't Qantas.