Welcome to the ODK forum, @dohji We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a real picture as your avatar because it helps build community!
I think a better option to explore might be to pull the collected data into your web app instead of trying to directly embed the entire interface.
- ODK Aggregate has options to publish the data, as well as API access: https://docs.opendatakit.org/aggregate-data-access/
- And if you're open to switching to the more modern ODK Central, it has both an OData live data feed and a REST API for integration and extensibility: https://docs.opendatakit.org/central-intro/