Unfortunately a chromecast attachement will be needed for all LG TV's here is a quick list of TV's that come built in with chromecast already.
https://www.google.com/chromecast/built-in/tv/
If the functionality of Alexa is what you are seeking for a new tv than the two options above are what you are seeking.
On the other hand if you are looking for a tv that can run all your accounts like Hulu, Amazon Prime, Netflix, YouTube etc. any smart tv will do. It all depends on what interface works best for you.
Hope this helps. Feel free to ask if you have anymore questions.