I want to share the method I used make my Sony Android TV operate as a display without a fire stick. It took only a few minutes. I followed this workaround using the Sony TV, a Windows 10 PC and an iPhone. There may be other ways to get the apk on the TV particularly if you have an Android phone. I hope this is helpful. I would not have been able to do it without the video and post linked below.
I followed the steps in the video below to get into developer mode and allow unknown sources on the TV. https://www.youtube.com/watch?v=-so_OA4W1PA
I installed the Sideload Launcher app from using the Google Play store on the TV.
I used my PC to sign into the Google Play Store and instruct it to install “ES File Explorer” on the TV.
I copied the link to the Taplist apk from mikey’s post below using my phone.
I opened ES File Explorer on the TV and went to Downloader > Add download and pasted the apk link from my phone in the file path using the keyboard in the “Video & TV SideView” app on my phone. There is a second line for file name but I left that blank. Without the SideView app, you could type the link but that would take a while using the TV’s onscreen keyboard. If you have an Android phone, you may be able to use ES File Explorer on your phone the send the apk to the ES File Explorer on the TV.
Once the sdk was downloaded in ES File Explorer on the TV, I clicked it followed by Install.
You can use the SideLoad Launcher app on the TV to open the Taplist app quickly.
When you open the Taplist on the TV, activation is the same as any other display. The activation instructions are linked below for convenience.