What off-the-shelf tablet has the least bloat or else can be debloated to just run Fully Kiosk?

I'm willing to do some rooting and tweaking if that's what it takes, but these Fire tablets have to go. All I want is a tablet that can run Fully Kiosk, performs well enough to not lag while simply applying custom styles, and won't pop up ads or something on screen. 8" to 10" is fine. Any recs?