Alexa can only turn off TV, no other controls

I have a smartthings hub and 2 Samsung TVs. The smartthings app on iPhone can fully operate the TVs but alexa cannot control volume or inputs and anything I ask it responds with “TV does not support that”. If I ask Alexa to turn off the TV, it does it successfully.

Note: This is not about not being able to turn on the TV, Alexa responds with “TV is not responding” when the TV is off which is a known and well documented issue.

I do not know if my TVs are supported but I assume they are since I am able to fully control them from the smartthings app. I can use all displayed functions in the app like change input, volume, mute, home, select, arrows, etc.

TV Models: UN65MU8500 and UN65KU6300
Hub Model: SmartThings V3 (IM6001-V3P)
Network: All devices and TVs are connected with Ethernet cables but I have tried to change them to wireless also which made no difference.

At this point, I just need an answer as to can I control my TVs with Alexa or not. If I cannot because of the equipment versions, I will just stop wasting time trying to make them work with Alexa.

Which shard are you on? Also check what states are listed for the TV in the IDE.

I am in North America. Would that make a difference for Amazon Alexa? By the way, yesterday both TVs disappeared from the SmartThings app and I was able to add the MU8500 back on using a code that came up on the TV but the KU6300 is no longer in the app. Still Alexa can only turn off the MU8500 and do nothing else with it. I am about to return the SmartThings hub because it has now become useless. With a single TV in it, when you say “Alexa, turn off the TV” it turns off my home office TV no matter where you were when you said it. The last thing I need is my wife to keep turning off my home office TV while she is trying to turn off the living room TV.