This text that automatically adds blank pages and releases overflow text seems a bit problematic

Help me take a look at this script, which was given by a friend on the previous forum.
But this script runs very slowly on CC 2020 and will cause the file to crash.

This is used to release unfinished overflow text and can automatically add blank pages.

Do you guys have better scripts to share?

//DESCRIPTION: Autoflow selected overset story  
  
  
(function(){  
          if (app.documents.length > 0  
                              && app.selection.length == 1  
                              && app.selection[0].hasOwnProperty("parentStory")  
                              && app.selection[0].parentStory.overflows) {  
                    app.doScript(fixOverset, undefined, app.selection[0].parentStory, UndoModes.entireScript, "Fix Overset");  
          } else {  
                    alert("There must be a selection that identifies the overset story.");  
          }  
  
  
          function fixOverset(story) {  
                    while (story.overflows) {  
                              var aDoc = story.parent;  
                              var lastTF = story.textContainers.pop();  
                              var lastPage = lastTF.parentPage;  
                              if (lastPage instanceof Page == false) {  
                                        alert("Story ends on pasteboard; no action taken.");  
                                        return;  
                              }  
                              var master = lastPage.appliedMaster;  
                              var newPage = aDoc.pages.add(LocationOptions.after, lastPage);  
                              newPage.appliedMaster = master; // may not be necessary  
                              var liveArea = getLiveBounds(newPage);  
                              var newTF = newPage.textFrames.add({geometricBounds : liveArea, layer : lastTF.itemLayer});  
                              newTF.previousTextFrame = lastTF;  
                              if (newTF.insertionPoints.length == 0  
                                                  && lastTF.insertionPoints.length == 0) {  
                                        // allows for paragraph style with startParagraph on specific page side  
                                        alert("Story is permanently overset.");  
                                        return;  
                              }  
                    }  
                    selectIt(story.insertionPoints[-1]);  
          }  
  
  
          function getLiveBounds(page) {   
                    var rO = page.parent.parent.viewPreferences.rulerOrigin;  
                    var bounds = page.bounds;  
                    if (rO == RulerOrigin.spreadOrigin) return returnBounds(page, bounds);  
                    var width = bounds[3] - bounds[1];  
                    if (rO == RulerOrigin.spineOrigin &&  
                                        (page.side == PageSideOptions.leftHand ||  
                                                  (page.side == PageSideOptions.rightHand &&  
                                                            page.parent.pages.length > 1)) ||  
                              (rO == RulerOrigin.pageOrigin &&  
                                        page.side == PageSideOptions.rightHand &&  
                                                  page.parent.pages.length > 1)) {  
                                        bounds[1] = bounds[1] - width;  
                                        bounds[3] = bounds[3] - width;  
                    }  
                    return returnBounds(page, bounds);  
                    function returnBounds(page, bounds) {  
                              return [  
                                        page.marginPreferences.top,   
                                        page.side == PageSideOptions.leftHand ?   
                                                  bounds[1] + page.marginPreferences.right :  
                                                  bounds[1] + page.marginPreferences.left,   
                                        bounds[2] - page.marginPreferences.bottom,   
                                        page.side == PageSideOptions.leftHand ?   
                                                  bounds[3] - page.marginPreferences.left :   
                                                  bounds[3] - page.marginPreferences.right   
                              ] ;  
                    }  
          }  
  
  
           function selectIt(theObj) {  
                    var myZoom = app.activeWindow.zoomPercentage;  
                    app.select(theObj);  
                    app.activeWindow.zoom(ZoomOptions.fitPage);  
                    app.activeWindow.zoomPercentage = myZoom;  
           }  
}())