Migration: migrate a Sharepoint Blog site to Sharepoint Online News Webpart

I am working on the migration of my SP Foundation 2010 site to SharePoint Online. In 2010, we had a subsite using the blog template we used for the news. I used a data view web element to show the posts of the blog subsite on my homepage. When I saw the News webpart in SPO, I thought I would replace that old functionality very well. I have migrated the subsite of the blog to a subsite in SPO and I tried to add the URL to the section of News sources in the configuration of the web part, but nothing appears.

Is there any way to import the data from that old blog so that the News website can consume them (apart from manually re-creating the pages in SPO)?