How to add the Islamic calendar in all the iPhone Calendar

My current location is Malaysia. I try to find a way to fix the problem of the Islamic calendar in all the calendar this year 2024. I cannot adjust the Hijri date /- 1 day for example in the iPhones calendar today is: 12 March 2024 corresponding to 2 Ramadan 1445, but the real date is 1 Ramadan 1445.

I tried below suggestion but still not solving my issue.

To do that, we recommend navigating to Settings and tapping Calendar. From here, turn off 'Alternative Calendars'. Next, go to Settings > Language & Region and change your region to Saudi Arabia. After that, head back to Settings > Calendar and enable the Islamic calendar in Alternative Calendars. With any luck, this should resolve the issue. If so, go ahead and change your region back to your current region and you should be good to go.

Please help me provide a solution.

[Re-Titled by Moderator]