File naming convention: Several brackets or one large for several tags

[TheDreadPirate]

I do not believe Jellyfin cares about the bracketed information. That's more embedding ephemeral metadata in the filename so it is not lost and kept consistent. None of my bracketed information is utilized by Jellyfin, but I still use it in order to assess the current quality or attributes of the file.

This was what I was getting at.  If you're not trying to do "versions" of a movie, what you do with the brackets doesn't matter.  For the purposes of metadata, Jellyfin does not use them.