In typo3, I would like to create a link to a news of the News System extension inside a tt_content using the RTE, how can I do it?
Sure. You need to look for the "linkhandler". Here is the documentation: https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ApiOverview/LinkHandling/Linkhandler/Index.html