People would like to be able to edit the language links that are coming from Wikidata in the page settings dialog. A link from there to Wikidata would probably also be a good first step.
T59929: VisualEditor: Add ability to edit local language links (non-Wikidata ones)
T64005: Using the language link tool in the sidebar when inside VisualEditor loses the edit without warning
T74178: Create widget to edit site links in the client