Replace the Amazon Fire Launcher with stock-like options like Nova Launcher or Microsoft Launcher.
Remove lock screen advertisements that typically require a fee to dismiss. amazon fire hd 8 10th generation custom rom
Disable automatic over-the-air updates to prevent Amazon from patching the exploits used by tools like Fire Toolbox. Comparison: 8th Gen vs. 10th Gen Customization Replace the Amazon Fire Launcher with stock-like options