The QQ parameter setting dialog box will appear. Locate the parameter settings tab and remove the √ in front of the "Show icon in taskbar" check box. After confirmation, the little penguin icon in the tray will disappear immediately. Thereby realize that first step of hiding.
Next, cancel the √ in front of "automatic pop-up message", and then mark "Use hotkey" in "Set hot key for extracting message". Now you can use the default hotkey "Ctrl+Alt+Z" or a custom hotkey. In this way, QQ can be activated by hot keys. Oh, by the way, please remove the "√" in front of "Friends Online Notification".
Then after opening QQ, drag the display screen showing friends online to any of the four corners of the display screen, and the second step of hiding is realized!
Finally, click the "Sound Settings" tab in the "QQ Parameter Settings" dialog box, and select "Turn off sound" in the "Sound Switch". Now, even QQ voice is gone.