This is basically what I do, except the quicker way without using ADB to remove anything. Might try removing the junk though to see if it makes a difference. Launcher Manager and Flauncher makes an Onn 4K very snappy. Hard to beat for $20 and a little setup effort. I used to use Firesticks for years, but they get so slow and constantly revert my launcher changes. Finally got rid of them all.