Thanks for the suggestion, I'll have to give that another try!
I've had success with Kodi in the past with my laptop but I've also had big performance issues on the firestick. To be fair, it's been a couple years since I tried that so I'll see if the newer versions perform better.
Setup your media (local or remote) library, and the scraper will enrich it with posters, synopsis, actors, etc.
[1] https://kodi.tv/