This is the original image, title, and description I want to update but I can't find the source file and text from the Blog and post settings. I checked the blog feed and can't find it. I can only enable / disable the ability to view, but I can't change the image nor update the content.
Hi Herlindros,
You can change up this blog header in the feed's settings. Go to Settings > Categories > All Posts Feed > Edit.
Once you click Edit, you can edit the text, design, and image.
Hope this helps. Feel free to let me know if you need anything else.