@Bev54: When turning the tablet on, are you unlocking it from an idle state, or powering it on? If you're unlocking the device, try heading to Settings > Battery and device care > Optimise now, followed by Memory > Clean now. You should also tap the Recents button in your Navigation Bar at the bottom of the screen (3 vertical lines) and close any apps that you're not currently using.
If the issue is occurring after powering the tablet on, then I'm not too sure what could be causing the performance issues. There is a short window after the device has booted up where your widgets and settings will load in, and this can cause the tablet to run slower than normal, however it shouldn't last for longer than a minute or 2. Is it the operating system in general that becomes less responsive (such as your swipe and touch interactions) or is it a particular app or feature?
