I’d second this. The organization behind it (https://calyxinstitute.org/about) is a long established non profit, their portfolio covers various cool projects. The vpn client itself is basically a rebranded version of https://f-droid.org/packages/se.leap.bitmaskclient, it it is nothing special.
This is your best option. I did do movie nights with friends during the pandemic in a similar way, but I used OBS Studio to create the stream and Monaserver to stream it to all users. I did not know VLC can handle the streaming to users directly, making this dead simple to setup without additional software. You just need to know how to configure your router to allow the needed port forwarding.