How do I prevent my phone from restarting after a System Update? Phone: Mobicel TRENDY_LITE
Android: 8.1.0

For about two days now, I have been receiving many Security and System Updates.

Every time an update is ready, my phone restarts without permission.

After each update, my phone seems slower than the last one.

What can I do? All the help is appreciated.
When a system update is performed, the phone reboots to allow the new files to take over the old (the old files will be removed from the system). On some devices, it is possible to delay the update, but when it (the update) is done, one has to restart the device.

If you don't want to update at all, then install a firewall and block the wireless update app from accessing the internet.