So it really depends on what you're streaming...10Mbps might work for one 1080p stream. More than that and you would be running into issues. It depends on a number of factors like coding of the video you're streaming. What protocol you're using for the VPN and so on and so forth If you have the time and a media server inside your home network (for example Plex or Jellyfin), maybe Tailscale might be a good test of what you want to do and see how that works. That would let you experiment with minimal effort.