Hi Alexey,
Thanks for contacting Syncfusion Support.
We have analyzed your query for Is it possible to use native (platform-specific) activity indicator instead build in. In SfPullToRefresh, it is not possible to use native (platform-specific) activity indicator instead of build-in as you required. Actually we will draw the arc whenever you pull the content based on the pulling threshold value. However, you can customize the refresh view properties like progress background color, progress stroke width, etc., Please refer the below UG link to know more about the pull to refresh customizations,
Also, please refer the below UG to know more about the SfPullToRefresh control and its features,
Please let us know if you need further assistance regarding this query.
Regards,
Jayaraman.