Amazon Fire HD 8" As Remote

[bearFNF]

I did also, but rarely use it I use my pixel C or my phone mostly.
You do have to sideload and adjust the screen DPI.

Take a look here:

Fire HD8 as a Roon Remote

https://kb.roonlabs.com/Android_Display_Settings

And here:
https://kb.roonlabs.com/Android_Display_Settings

Search is your friend…just sayin’