printing package in flutter does not work in flutter build web mode

im working on a project that require in a certain moment to generate and print a document. I've done this using pdf and printing packages. It all works fine if im in the debug mode, but not in the builded version.

I also added the script recommended for the web:

<script>
  var dartPdfJsVersion = "3.2.146";
</script>

This is the code i used:

import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:printing/printing.dart';
import 'package:sostituzione_docenti/providers/gestione_docenti_provider.dart';

import '../classes/control.dart';

class PdfService {
  static Future<void> printOrario(
      List<List>? orario, DatoDocente docente) async {
    final doc = pw.Document();
    List<String> header = ["Ora/Giorno", "Lunedì", "Martedì", "Mercoledì", "Giovedì", "Venerdì", "Sabato"];

    doc.addPage(pw.Page(
        pageFormat: PdfPageFormat.a4,
        orientation: pw.PageOrientation.landscape,
        margin: const pw.EdgeInsets.only(top: 50, right: 100, left: 50, bottom: 100),
        build: (pw.Context context) {
          return pw.Column(
            children: [
              pw.Text("Orario di ${docente.cognome} ${docente.nome}"),
              pw.SizedBox(height: 10),
              pw.Row(
                children: [
                  for (int a = 0; a < header.length; a++) ...{
                    pw.Expanded(
                        child: pw.SizedBox(
                          height: 50,
                          child: pw.Container(
                              decoration: pw.BoxDecoration(
                                  border: pw.Border.all(color: PdfColors.black),
                                  color: PdfColors.green100),
                              child: pw.Center(child: pw.Text(header[a]))),
                        )),
                  }
                ],
              ),
              for (int i = 0; i < Control.maxH; i++) ...{
                pw.Row(
                  children: [
                    pw.Expanded(
                        child: pw.SizedBox(
                          height: 70,
                          child: pw.Container(
                              decoration: pw.BoxDecoration(
                                  border: pw.Border.all(color: PdfColors.black),
                                  color: PdfColors.green100),
                              child: pw.Center(child: pw.Text("${i + 1} ora"))),
                        )),
                    for (int j = 0; j < 6; j++) ...{
                      pw.Expanded(
                          child: pw.SizedBox(
                            height: 70,
                            child: pw.Container(
                                decoration: pw.BoxDecoration(
                                    border: pw.Border.all(color: PdfColors.black),
                                    color: orario![i][j] != null
                                        ? PdfColors.amber100
                                        : PdfColors.white),
                                child: pw.Center(
                                    child: orario[i][j] == null
                                        ? pw.Text(" ")
                                        : pw.Text(orario[i][j]))),
                          )),
                    }
                  ],
                )
              }
            ],
          );
        }));

    await Printing.layoutPdf(onLayout: (PdfPageFormat format) async => doc.save());
  }
}

Does anyone can help me?

Edit: those are the errors i get in the browser:

Uncaught Unsupported operation: Platform._operatingSystem