Download Instagram Reel with end points
?__a=1&__d=dis . These End points Gives reel download url and some json Response.
below pic for how to put endpoints like this.
Just Create reel Download with this tutorial.
Add above end points to Instagram reel link and get response.

Create onReq Component and add try catch code or block.
Just put below code. 
Getting Whole Response add this
JSONObject o1 = new JSONObject(_response);
Next get video link from response 
link = o1.getJSONObject("graphql").getJSONObject("shortcode_media").getString("video_url");
Above code for getting video link. Link is String to use video URL.
and finally you will get video URL of Reel with end point.