Check this answer: https://eshwaren.medium.com/enable-emmet-support-for-jsx-in-visual-studio-code-react-f1f5dfe8809c
Also try restarting your VSC after modifying the settings.json, I got that one too.
For VScode version 1.69.0 div * 5 it's not working. Even ul>li * 4 is not working. for making it workable. we have to write like this div * 5 ctrl+space or ul>li * 5 ctrl+space. It is working 100%.