You can remove the Latest News feed from your Dashboard by selecting the Settings option in your CMS, click on the General tab and untick the “Enable Latest News?” option. You will need to click Save to confirm the changes.
Alternatively, you can change the feed used with Latest News by running the below SQL statement:
update `setting` set value="https://example.org/myrss" where `setting`="LATEST_NEWS_URL";
To be able to run the statement, you will need to follow the instructions in the below linked guide: