I just updated my HiSense TV's AndroidTV firmware and noticed afterwards that my SmartTube app had been deleted. I guess it makes sense because Google owns YouTube and Android and they want you to watch their YouTube ads or pay to make them go away. I'll be using my Fire Stick exclusively from now on.
Seems like an extreme reaction. Just reinstall it.
You couldn't pay me to go back to a firestick.
I've had similar issues, and what worked for me was disabling Google play protect 👍🏻
I have the Hisense 55" TV as well and when i updated mine it did NOT delete anything you have to turn off PLAY protect on your google account to stop it from deleting your UNKNOWN apps .
I have this machine as a backup but don't use it much because I use the Shield most of the time and the same goes with any of your android systems if you login with your google account make sure you turn play protect off so it doesn't delete any unknown apps
Just side load it back on 🤷♀️