请尝试以下代码：

extension ExtendedString on String {
  String toMarathi {
    return this.replaceAll("0", "०").replaceAll("1", "१").replaceAll("2", "२").replaceAll("3", "३").replaceAll("4", "४").replaceAll("5", "५").replaceAll("6", "६").replaceAll("7", "७").replaceAll("8", "८").replaceAll("9", "९");
  }
}

"${DateTime.now().day}, ${DateTime.now().month}, ${DateTime.now().year}".toMarathi()

尝试下面的代码参考一些链接GlobalMaterialLocalizations，initializeDateFormatting：
导入以下程序包

import 'package:intl/date_symbol_data_local.dart';

在initState内添加initializeDateFormatting()

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

您的日期代码

DateTime currentDate = DateTime.now();
String todaysDate = DateFormat('d MMMM, yyyy', "mr").format(currentDate);

print(todaysDate);

您的小工具：

Text(todaysDate),

完整代码：

import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:intl/date_symbol_data_local.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({super.key});

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  @override
  void initState() {
    super.initState();
    initializeDateFormatting();
  }

  DateTime currentDate = DateTime.now();

  @override
  Widget build(BuildContext context) {
    String todaysDate = DateFormat('d MMMM, yyyy', "mr").format(currentDate);
    print(todaysDate);
    return Scaffold(
      body: Center(
        child: Text(todaysDate),
      ),
    );
  }
}

结果-〉