Watch downloaded movies on dumb TV -- No internet

All you need is a media player
You can get something for $49

Now if you want remote control
Built in storage etc.. Like your. Wd, then it is going to cost more money
You can even do this with your smart phone or tablet using a OTG cable (on the go)

I have a
MEDIASONIC digital recorder player, that will play recorded/downloaded content from USB to the tv using HDMI cable, and they are available on Amazon for around $39