A warm welcome to HP Support Community!
Since you have tried all possible troubleshooting steps mentioned in this document, I'm afraid, its a possible printhead failure. Please call HP Support to obtain all available repair/replacement options. You may use the following steps to contact your regional HP Support:
1) Click on this link.
2) Select your product type below.
3) Enter the serial of your device.
4) Select the country from the drop-down.
5) Select the chat or get phone number options based on your preferences.
6) Fill the web-form and proceed further.
Have a great day!