I guess I missed most of the earlier convo on this re fire/android vs roku.
it is mostly the player/ui in roku that beats android/fire hands down.
my plex data with chapter/video thumbs was nearly 600 gig.
in fact I just a few days ago migrated from my raid 10 array that was holding plexdata, to a dedicated 1tb SSD and still rebuilding the thumbs.
large plex data is simply ‘the cost of doing business’ if u want thumbs.
see also related thread @ Video Preview Thumbnails on Apple TV: Why can Infuse 6 do it on the fly, yet Plex still not at all (after 4+ years in the making)!?