So I wonder if it possible to stream content from PC to my Android TV without using an APP like Plex or the Wifi Direct which disconnects me and force me to use Windows Media Player instead of a better streamer like VLC PC and TV are in the same network
The VLC Android TV app just got network file support. Set up your media in a NFS and you should be able to navigate to it. Other apps to check out include Kodi and Archos.
Why don't you want to use Plex?
Are you not able to use VLC for Android TV? They just added new features to it.
How about VideoStream
This is exactly why Plex exists. Maybe try an alternative like Kodi? Or are you wanting to go the SMB share or DLNA route and just browse a boring file tree to pick something to watch?