custom_platform_device_id 1.0.8

You can get device id from platform - linux/mac/windows/android/ios/web.

example/lib/main.dart

import 'package:flutter/material.dart';
import 'dart:async';

import 'package:flutter/services.dart';
import 'package:platform_device_id/platform_device_id.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String? _deviceId;

  @override
  void initState() {
    super.initState();
    initPlatformState();
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> initPlatformState() async {
    String? deviceId;
    // Platform messages may fail, so we use a try/catch PlatformException.
    try {
      deviceId = await PlatformDeviceId.getDeviceId;
    } on PlatformException {
      deviceId = 'Failed to get deviceId.';
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _deviceId = deviceId;
      print("deviceId->$_deviceId");
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
        ),
        body: Center(
          child: Text('Device ID : $_deviceId'),
        ),
      ),
    );
  }
}