I just asked Google Bard about the most popular social media platforms in China. It let me know about the WeChat app. I am just wondering if you could please tell me if I can try to build a new WeChat Android app for the USA? Or, would I be in international trouble? I mean, it wouldn't be a direct copy of the WeChat app. But, it would be based on that idea.
Probably better to wait until Elon Musk has finished recreating X in weChat's own image
To answer your question, as long as you do not infringe any copyright issues - content/images/methods, you should be able to have a go at creating your own clone of weChat in AppInventor, this may mean that you would have to leave out some features.