Tiki automatically and silently renames uploaded files to strip special characters and to apply headline-style title case (which only makes sense in English, in the US and UK, and that's pretty much Americentrism to me) instead of leaving it be.
So if I upload a file named "2022-08-25 tiki tracker item metadata modifications not showing up in email notifications.mp4" to a tracker item here, I end up with a file named "2022 08 25 Tiki Tracker Item Metadata Modifications Not Showing Up In Email Notifications". And if I were to upload something with personal names that require special casing, such as noble French names like "Marc de la Montagne" or "Roxie de la Sablonnière" or dutch names with unpredictable capitalization like "Adriaen van der Werff" or "Ariën Van Weesenbeek", it would get f'ed.
The current title casing is not even correct for English headlines, where minor words (such as "the", "of", "and", and I would say "in") are not supposed to be capitalized. Proof here and here.
So I would say, please don't mangle filenames. At most you can offer/prompt the user about whether they want it to be auto-standardized in that way, but frankly I'd tend to think it's better to just leave the thing be as the user wrote it, except maybe the underscore characters that you can offer to replace by spaces or hyphens...