Hello Hoan,
We do not currently have a Flutter port of our Video SDK and I am unsure if there are plans to support this in the future.
I can do some more research on this issue and see what information I find.
The @zoom/videosdk you mentioned on NPM is also available via the unpkg CDN and might work for your use case if you just want to embed the <script> import in your resulting html for deployment.
<script src="https://unpkg.com/@zoom/videosdk@1.3.0/dist/index.js"></script>