Could you check this page about connection issues? If it doesn’t help, you may need to try a Factory reset as a last resort. Please share us your observations.
Also when power the device directly it’s not connecting I always need to power the same through USB-c Multiport Adapter or Docking Station then only it’s connects or show the device.
Glad to know that you are able to use the device. Please note that the device can be connected via either TCP/IP or USB mode. Both modes cannot work at the same time. You may refer this page to know about changing connection modes. If you are powering the device via power adapter, you may consider using TCP/IP mode. For USB mode of connection, device needs to be connected to your workstation.