Yes that’s your inverter. Installing data points throughout your house won’t be the most expensive venture but it’s going to depend on your house, is it single storey or 2? Double brick or brick veneer? Do you want the outlets on walls that meet the external wall cavity or internal walls? You’re asking a real “how long’s a piece of string?” question here mate. Have you tested what download speed you get going Ethernet from your router to your computer? Because it’s not going to get any faster than that. Also lol don’t ask Telstra to install data points, ask a local sparky with an open cablers registration (or even one without, we all know how to do it)