I do something similar, been doing it for years and I don't recall all the rational and there could be better ways today.
What I do is put the year in the genre field in the movie metadata. When you view by genre, you will have folders with year labels. (I actually use a text string like "Video Clips - 2018" as I organize clips into a couple diferent clip categories, Video Clips in this example)
Dunno how you want to do that in your work flow, but I think after importing into the itunes library, you should be able to select the movie, get info, and in one of the tabs you can edit the genre. Just replace whatever is there with the year.
For reference, I edit the meta data before adding the movie to iTunes because I'm often adding 10-12 clips at a time.
I export the clip from my video editor as a master file (mov). I use handbrake to convert to an applTV/iTunes friendly file (m4v) (handbrake was doing a better job than the built in mac stuff). I use subler to edit the m4v genre data, sometimes the title field (there are a bunch of items you can edit like the sort order). I defined a custom metadata set that suits my purpose. Finally I drag/drop the edited m4v into the "automatically add to iTunes" folder located where the iTunes library is. Like magic iTunes takes care of the rest.