Yes the chart element loads instantly, but it is the searching for data that takes time.
I have created a test app where you can see that how my way could work. (Notice the condition on the chart and spinner element) I also struggled some time ago with this problem, but there is definitely a solution! 
Demo: https://chartloadingtest.bubbleapps.io/
App editor: https://bubble.io/page?name=index&id=chartloadingtest&tab=tabs-1&subtab=App%20Data