VLC player paired with a network share does pretty much everything I need to watch local media. I have a Jellyfin instance, and I do like it, but I often find myself falling back to VLC for one reason or another.
That's true. Years back, you could cast to Fire TV from the android VLC app. But I recall it not working very well, and I think support for Chrome Cast was entirely removed at some point? I don't know, I completely gave up on the Fire TV sticks. Calling them "weaker" is even being charitable, with all the issues I constantly ran into.