Hi Ansh- Julianne from Mixpanel Support here!
I hate to be the bearer of bad news, but autocapture is currently only available with the JavaScript SDK. This means for Flutter, you would need to manually track the events you're interested in, such as page views and element clicks.
I definitely recommend submitting your use case and request for Flutter autocapture via the 'Submit Feedback' form (under the ? menu). This will flag your use case and support of the feature to the Product team. They use the logged gaps to develop future releases and improvements of the product.
