So, I don’t use The Renamer, but I have an alternative workflow that I can share.
For my library, I don’t only want the files named correctly, but I also want to ensure that they have correct embedded tags including artwork for applications beyond Plex. So typically I run a utility to automatically apply movie / TV info to the files, and then a tool to rename the files based on the embedded metadata.
On Windows I have used MyMeta from the Microsoft Store and MetaX, which is also available for Mac. Both of these utilities can look up information in TTVDB and TMDB and tag files automatically.
For renaming (and to “fix up” tags for consistency if needed), I use MP3Tag. You can set up a custom renaming action using a template that matches Plex naming conventions. Although MP3Tag is mostly known for tagging music files, it also works with MP4 files, and is a kind of “Swiss army knife” of metadata editors.
All of these tools have batch modes that can work with multiple files at once.
It may sound a bit fussy, but I like the control this approach offers.