I don’t really use the SmartThings app as a Q70 remote control, but when the HDTV is on, I can see this
I can also see input information. Like the channel it’s currently tuned to on the devices three Dot menu.
I do use the HDTV SmartThings integration for voice command control. Below is one of my previous posts about the Alexa voice control integration which also works from the Alexa app on my Android devices too so I don’t believe you need an Alexa/Fire TV device. I have the Alexa service and SmartThings connected. I can mute/unmute, change channels and select DTV or HDMI input changes, and so on using Alexa voice commands.
Also, if you have SmartThings devices (Hub, motion sensors, and stuff), the HDTV is now a SmartThings device. So, it can be used in SmartThings Automations. For example, like when the motion sensor in the living room is triggered in the morning, then turn on the HDTV to source TV for over the air so I can watch the morning newscast.