Once is enough. You're not being ignored, but as far as I know there is no way. Chromecast, Roku and FireTV all require internet, and the Stylo 3 has no MHL output. So you can get Wifi or you can get a different phone.
I'm curious -- why are you posting in the Tab S4 forum when you're asking about the Stylo 3? And in your other posts, you ask the same question about the LG G Pad 7.0, as well as the Tab S4. Do you have all of those devices?
I will merge this post with the other one in the LG forum.