As the title says, are they on your radar? I assume there are significant challenges that explain their absence, ie. if it were easy, they would already exist...
It mainly comes down to number of hours in the day. I'm already stretched pretty thin.
That said, I have run the android app on a firetv device in the early days, so there it possible it could make an appearance on the amazon store at some stage. I don't really know anything about developing apps for roku at this stage.
After things settle down with v5, I intend to get back to improvements on the Android and iOS apps. I may take a look at firetv support during that time.
I have the NPVR New Client working well to a v5 server on an old 32bit FireTV stick under Kodi. Unfortunately as Amazon have tied the device down some things are lot more difficult to do so it does not work as nicely as on say a RPi.
Chris
NextPVR Server - HP N54L Microserver, Windows 10 - Storage 2 X 3TB - Tuners DVBSky S952 Twin DVB-S/S2 PCIe, Hauppauge Twin DVB-T2 USB, Telestar Digibit R1 Sat>IP Server.
Clients:- 2 X RPi3, 1 X RPi4 and Acer RL80 Celeron Nettop all running NextPVR New Client on LibreElec.