Creating multiple pdfs from a single RDLC report as per pages

If you want to play with PDF (merge multiple into one or split one into multiple), would suggest take that as a separate task here instead of driving it through RDLC report.

Use any free thrid party library that can split a pdf into pages as per your need. Example, I would take the RDLC report and then use that as an input to PDFSharp to break it into multiple pdf's per page.
Example:

// Get a fresh copy of the sample PDF file
const string filename = "Portable Document Format.pdf";
File.Copy(Path.Combine("../../../../../PDFs/", filename),
Path.Combine(Directory.GetCurrentDirectory(), filename), true);
// Open the file
PdfDocument inputDocument = PdfReader.Open(filename, PdfDocumentOpenMode.Import);
string name = Path.GetFileNameWithoutExtension(filename);

for (int idx = 0; idx < inputDocument.PageCount; idx++)
{
// Create new document
PdfDocument outputDocument = new PdfDocument();
outputDocument.Version = inputDocument.Version;
outputDocument.Info.Title =
String.Format("Page {0} of {1}", idx + 1, inputDocument.Info.Title);
outputDocument.Info.Creator = inputDocument.Info.Creator;
// Add the page and save it
outputDocument.AddPage(inputDocument.Pages[idx]);
outputDocument.Save(String.Format("{0} - Page {1}_tempfile.pdf", name, idx + 1));
}

Reference: PDFsharp Sample: Split Document - PDFsharp and MigraDoc Wiki[^]