@Lawedeke 

Hi, are you able to connect a laptop via cable to the ISP modem to make sure the internet connection has been restored?

It could also help to identify whether there might be any change to the internet connection, such as a new internet type.

After that, if the PC works great, you could set a different Deco as the main Deco to see whether it helped:

How to Set up the Satellite Deco or a new Deco to be the Main Deco

For more details, please also refer to:

Unable to connect to the Internet

Thank you very much and best regards.

  @Lawedeke 

Thanks for the feedback.

In this way, have you checked the IPV4 settings under Deco APP>More>Internet Connection?

It is blank or 0.0.0.0?

It is also suggested to refer to Unable to connect to the Internet

I still think the internet connection from the ISP side hasn't fully recovered and have you tested with another third-party router?

Best regards.