I think he already tried uninstalling/re-installing. I ran a search through the thread and found a few results, but they all pretty much said a factory reset is required.
I'll let you guys know, when I get my new tablet, how the Toolbox works on it. I'll definitely be fooling around with installing nova Launcher, hiding the home button and using an alternate nav bar/app. I'll also let you know what I find out about the IP addresses to block to stop updates.
If you are able to stop the firmware from updating during the OOBE and Registration process on new tablet, the most important system app to disable and leave disabled is:
DeviceSoftwareOTA (com.amazon.device.software.ota)
This is the app that downloads the individual System Apk updates, and once the Firelauncher (aka Home Pages) & Special Offers (com.amazon.kindle.kso) individual apk's update to the latest versions you are locked-out of changing the Firelauncher and blocking Home Screen Ads (Special Offers) permanently. But if you first can disable DeviceSoftwareOTA, HomePages, and SpecialOffers; then you can proceed with connecting to network and receiving the full firmware update "FireOS version: 7.3.2.2 (PS7322/2519)" -- I was able to update the Dec./Feb./Mar. firmwares all the way to the latest firmware and keep HomePages and SpecialOffers disabled "persistently" on an old FireHD 10 (2019), but the minute I enabled this package: (com.amazon.device.software.ota), then the latest HomePages and SpecialOffers updated, and I was F*ck'd.
Also, what I noticed with recent firmware is that having the most recent versions of Google Play Store, Google Play Services, & Google Assistant all installed were crashing Services all the time in the background if I left Amazon Appstore (com.amazon.venezia) Enabled, so Disabled Amazon Appstore and tablet running smooth again.
Now I'm using an AutoStart app to launch into Evie Launcher from lockscreen, and with the 'Fire_Toolbox/Lockscreen_Management/Locksreen_Shortcuts/Customize_Lockscreen_Shortcuts/' tool can set a lockscreen shortcut to also open direct to Evie Launcher on a corner swipe.
For navigation am using XDA's Navigation Gestures app as alternative NavBar app, and not enabling any swipe or press to activate Home-action. If I open Recents and Clear-All then I'll be taken back to HomePages (firelauncher).
Recommend installing SystemUI Tuner by Zachary Wander to persistently modify the QuickSettings tiles.
And to Firewall system apps that are now protected from being completely disable, I've installed RethinkDNS (https://rethinkdns.com), which can firewall individual user & system apps via the VPN service and works great as an Ad-blocker with its DNS filters lists.