Why all calendar templates start with Sunday?

I don't know if it affects the templates, but the following link describes the method of changing the first day of the week in windows, so it is possible that some templates actually access this setting. I will be interested to know the result.

https://support.microsoft.com/en-us/office/set-the-first-day-of-the-calendar-week-and-change-calendar-work-days-8f009e32-e05e-47fd-809f-7b1d82d00c3e

Thank you. Doesn't work since the templates are VBA based. I tried moving sunday to the back but then I could not use it for another year.

I searched and they do have some (very little) templates with (MON) in the title indicating they start with Monday. Sad they are not looking the way the others do. But I just started working on my own so... But it would be normal to have that option in the code, to set Monday as first day of the week.

From my understanding sunday as first day is due to religion reasons but in most parts of the world daily logs and plannings are kept for business so Monday is first day of work.

do you want this kind of calendar？

No, I want Microsoft to publish same templates that start Monday and Sunday. So we can select. There are a lot of templates looking really good but you can't use them since they do not have Monday first option.