I bought a refurbished Fire HD 8 (2017) the other day and installed the Google Play Store to enable installation of conventional Android apps and even installed a new launcher; the Fire interface is not to my liking.
Roon remote has been running well so, in the end, I added a remote for about $50 and an hour of work.
The HD 8 is not as snappy as my Google Pixel 2 which runs stock Android but it’s plenty responsive and has a nice display for controlling Roon.
I really wanted an iPad for a remote but $50 vs $300+ enables me to spend more on music or gear.