I don't think there is any public API to get this data. Options you could use are:

• Automation of Android phone (for example using Appium: https://github.com/zxkane/WeChatMoments)
• Automation of Windows version of WeChat (for example using pywinauto: https://github.com/middleclicker/Wechat-Moments-Scraper)
• Extraction of Moments data from the WeChat app cache: https://github.com/Atlasoin/wechat-moments-exporter
  • Guides:
    • https://atlas.xlog.page/how-to-export-moments-and-post-on-chain?locale=en
    • https://atlas.xlog.app/A-Full-Guide-to-Export-WeChat-Data-(Availiable-Only-for-WeChat-User)?locale=en