amCharts disabling animations

Remove am4core.useTheme(am4themes_animated) line from your code.

https://www.amcharts.com/docs/v4/concepts/animations/#Using_Animated_theme

In amCharts serial charts animation is not enabled by default. If it is on for you, there is probably a line in your chart config which sets startDuration property. Just remove it, or set it to zero to disable all animations.