Tidal HiFi is the more expensive subscription, and offers MQA. Tidal Premium is their lower res one at 320kbps and no MQA.
Docoding or "full unfolding" happens only within an MQA-certified DAC. and most mobile devices do not have that. In fact, most mobile devices can't do anything above that 320kbps rate. I have to use BubblePnP app to get the "CD quality" 1441kbps rate of Tidal HiFi on my phone or tablet to my headphones (KEFM500) or earbuds (KEF M100.)
I don't know what a Firestick does, but it should at least do the HiFi version.