EzCast | How to cast to a projector by connecting to it's Wi-Fi Hotspot and still keep internet Wi-Fi connection?

Two days ago, my dad brought a projector that has a weird miracast system that works when something connects to **it's** wifi network and mirrors the screen using an app called EzCast. The thing is, I want to use it to stream videos on my phone while mirroring my screen. The projector does not connect to normal wifi networks, but instead, it hosts its own network where the device to be mirrored/ cast from is to be connected to. So If I have to watch something on the projector, I lost my internet connection. - Is it possible to connect to two wifi networks at the same time? Or - Is there any other way to get the desired result?. (stream videos online to the projector). Thanks. Please pardon the messy wording. I'm typing this on my phone and am an ESL speaker.