You need a file managing software which supports the share functions. I used FE FileExplorer for it (theres a free version), but I guess it will work with other apps as well. In FE you can create and establish a network connection to the NAS and navigate to the file intended to play on VLC 3.2.x. Do not open the file, stream it to VLC. In FE hit the three vertical dots behind the file and hit "Stream to...", then select VLC. VLC app will open. Hit "play" and video stream to the network source starts. While viewing, FE could be closed, because its not needed anymore.
Thanks for the tip. The first time I tried it, it worked. Now it has stopped working for no apparent reason. Fortunately FE includes a media player so I don't need to stream to VLC. I loved VLC, it did everything I wanted it to, but now it's ruined. Pity.