use the FKB “screensaver” and set the screensaver URL to "dim:"
depending on the screen technology (OLED screen will be OFF and black, regular LED screen will just be black, some backlight shining through). when you touch the tablet the screen will revert to on
i use this method on a 50$ Amazon Fire 7 (most current) and it works a treat. tablet does not revert to any lock screens or anything. its dark all day until you touch it or it gets motion activated (FKB).
so yeah, the amazon fire tablets are annoying, but they can be made to work with some settings in FKB.
and i use a 3D printed mount for it:
I have a samsung tab pro 8.4 as another panel. I used a router and made a “picture frame” for it. i’ll try to post pictures to night if anyone is interested.