Dragonfly amp? And mars 2 projector

A while ago you talked about the Dragonfly Amplifier.
I have the Mars 2 pro projector that Fr. Robert reviewed. This is the second version. I Loooove it. But, some movies I stream are at a low volume. I use my ipad to stream to a Chromecast Ultra device. Works great. Except that some movies are streamed at a low volume. I tried to up the mars volume to 100% and then I up the chromecast volume to 100%. Treaming a starwars movie from the new Disney network, the volume is soooo looow; I can hardly hear the audio. I have tried bluetooth ear phones and the same. These are the Surge 3D headphones that Alex Lensay recommended on Mac Break Weekly. Still Low volume. Other shows like most Youtube videos are at normal volume.
That said I am looking for an external amplifier that I can use with external speakers or bluetooth earphones. I just wondered if the Drangonfly was a good fit?
I really want to know how much amplifing I will expect. If the volume is not loud enough then the amp is useless for me and if it will work with the Mars 2 projector.
Bluetooth output is a must. The Mars 2 pro has a 3.5mm output plug and USB plus HDMI out. But I would like to use bluetooth to external headphones. I don’t know if I could split the HDMI and have the audio go into the amp. for a 5.1 or 7.1 channel output. My headphones are supposed to do 7.1 audio output. Just trying to find options. A battery operated or self powered amp would be nice but not a must have feature.
I see that there are a lot of cheep amps on Amazon so I am not just set on a Dragonfly amp.

Thank You,