One thing I discovered that I don't like about the Fire Stick is that if you are disconnected from the internet all your Home apps will be unavailable. So if you're using Kodi to stream movies from your NAS you're out of luck until you get your internet back up.
There's a pseudo-app for Youtube on the Amazon store. It does nothing more than to link to Youtube either via Silk or Firefox browser depending on what you have installed. This is what I'm using and it works fine.
Actually there's a work around if the home launcher is disabled because of no internet. If you have the firetv remote app installed on your phone you can launch your apps directly from there.
Second work around is to press and hold home button on your remote then go to settings then go to manage installed applications then select the app you like then just launch the application.
I was able to load plex and stream a video from my local network with no internet at all (
You need to disable Plex Authentication under settings on your Local Network).
Also run FX file explorer and stream videos over local network via SMB.
Yup, I was able to try the pseudo youtube app. But I wasn't satisfied because it plays back 60fps videos only at 720p/30fps.
Smart Youtube TV can play it back better at 1080p/60fps.
