@Harry50 

“Show on Lock Screen” means the push notification, not camera liveview screen. We cannot automatically bypass the phone's lock screen to show camera liveview screen when someone rings the doorbell. 

A quicker way to see camera image is to choose the ring call notification option, you can see the camera feed after answering on your phone.

If you have an Alexa display device at home, you can set it up to automatically show the camera feed when someone rings the doorbell. Unlock New Smart Home Capabilities with Alexa Integration on Your Tapo Camera/Video Doorbell ​​​​​​​

  @Harry50 

You may check the signal strength of the doorbell, improve device's network connection if the signal is weak. How to check and improve the network connection stability of Tapo&Kasa smart devices

If you prefer to see the camera image immediately, consider keeping the camera live stream open all the time with a dedicated device in the local WiFi network, such as a tablet. However, note that the local stream might be interrupted when there are multi-streamings.