Split the batch into multiple pages according to the red frame

If it's possible for you to add marks to indicate the areas to be cropped, I think it's easier with square-type annotations.
In fact, the difficulty for you will come from the number of areas to indicate in the document, but if they're already drawn, that simplifies things a bit...
I've used this method in the past to crop different text areas in a document and extract them one by one.
This is an answer that certainly won't suit everyone, but it shows a possibility of using in JavaScript.
Here's a script that will do this:

var nbPages=this.numPages;
for (var p=0; p<nbPages; p++) {
	var zones=[];
	var annots=getAnnots({nPage:p});
	if (annots!=null) {
		for (var i=0; i<annots.length; i++) {
			if (annots[i].type=="Square") {
				zones.push(annots[i].rect);
			}
		}
		for (var i=0; i<zones.length-1; i++) {
			this.insertPages({
				nPage: p,
				cPath: this.path,
				nStart: p
			})
		}
		for (var i=0; i<zones.length; i++) {
			this.setPageBoxes({
				cBox: "Crop",
				nStart: p+i,
				rBox: zones[i]
			})
		}
	}
	p+=zones.length;
	nbPages+=zones.length;
}
var annots=getAnnots();
for (var i=0; i<annots.length; i++) {
	if (annots[i].type=="Square") annots[i].destroy();
}
this.saveAs(this.path.replace(/.pdf$/i,"_Cropped.pdf"));

Below, you will find your example on several pages before and after cropping.

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