Sorry to hear about the trouble you are running into. I wanted to follow up and see I could be of any help. I found an article that has some troubleshooting steps that could be of help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.
I tried the steps in the article with no success. I don't think I have needed to have services linked to my google account before but looking on GoogleHome app under Videos and Photos it shows none of my services are linked. Just for fun I tried saying " open IT Crowd on Netflix" and it opened Netflix and started IT Crowd but when I backed out of Netflix and asked " open Netflix" it gives me the usual "OK, launching Netflix on the Family Room TV" but never actually opens it. It just started doing this recently. Hope this is helpful.
@Jake, thanks for the help.
@9erfan, I appreciate your most recent information. Since you have already tried most of the troubleshooting steps, including doing the steps on the link @Jake has provided. I need to have more information to know where to start. Does your TV have a Chromecast device or a built-in Chromecast/Google Assistant to it? Have you tried giving commands to other TV’s? Could you unplug and replug your TV, Chromecast(if available), and your Google Home/Nest device.
Keep me posted.