when I turn the switch off/on all others switches turn too

your problem is that you are using a single Boolean for all the list's users, you have many options on how to solve this problem, this starter code based on your code might help you:

import 'package:flutter/material.dart';

    void main() async {
      WidgetsFlutterBinding.ensureInitialized();
      return runApp(MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Home(),
      ));
    }
    
    class Home extends StatefulWidget {
      @override
      ViewAllOperators createState() => ViewAllOperators();
    }
    
    class OperatorInfo {
      String name;
      String photo;
      OperatorInfo({required this.name, required this.photo});
    }
    
    class ViewAllOperators extends State<Home> {
      static List Operators = [];
      Map alarmIsActiveMap = Map();
    
      // @override
      // void initState() {
      //   alarmIsActive = Global.shared.alarmIsActive;
      //   super.initState();
      // }
    
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            elevation: 0,
            title: const Text(
              "View All Operators",
              style: TextStyle(color: Colors.black),
            ),
            iconTheme: const IconThemeData(
              color: Colors.black, //change your color here
            ),
            centerTitle: true,
            backgroundColor: Colors.white,
          ),
          body: FutureBuilder(
            future: giveMeUsers(),
            builder: (context, snapshot) {
              if (snapshot.hasError) {
                return const Text(
                  "Something went wrong",
                );
              } else {
                Operators = (snapshot.data ?? []) as List;
                return ListView.builder(
                  itemCount: Operators.length,
                  itemBuilder: (BuildContext context, int index) {
                    return ListTile(
                      leading: const CircleAvatar(
                        backgroundImage: NetworkImage(
                          "https://cdn-icons-png.flaticon.com/512/3135/3135715.png",
                        ),
                      ),
                      title: Text(Operators[index]),
                      onTap: () {},
                      trailing: Switch(
                        value: alarmIsActiveMap[index] == null
                            ? false
                            : alarmIsActiveMap[index],
                        onChanged: (bool isEnabled) {
                          setState(() {
                            alarmIsActiveMap[index] = isEnabled;
                            Global.shared.alarmIsActive = isEnabled;
                            isEnabled = !isEnabled;
                          });
                        },
                      ),
                    );
                  },
                );
              }
            },
          ),
        );
      }
    }
    
    Future<List<String>> giveMeUsers() async {
      await Future.delayed(Duration(seconds: 1));
      return ["user1", "user2", "user3", "user4"];
    }
    
    class Global {
      static final shared = Global();
      bool alarmIsActive = false;
    }

where the output would look like: