I also use openScale from F-Droid, in combination with this Bluetooth scale:

https://sanitas-online.de/de/p/sbf-70-bluetooth-glas-diagnosewaage/

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.

Agreed. From a privacy perspective, it is a lot safer to run the app in an environment where you have admin control. E.g. disable when not in use, block access to sensitive device information, limit background and network activity as much as possible.