I've just bought a nice JVC LT-55CF890 TV with Fire OS Built in. The only problem is it keeps going to sleep after 5mins when paused or inactive. A real PITA when listening to radio, or when paused in a netflix show if you want to make a cup of tea or take a comfort break, you have to turn the tv back on, open the app, and select resume. It feels like the "Sleep Timer" is always enabled, there is no "Never" option.
OS Version - 22.214.171.124 (PS7212/1296)
Fire TV Home Version - 6220057.1
Model - JVC_LT-55CF890