This situation is easy to fix. Change the calendar so there are 13 months with exactly 4 weeks in each month, for a total of 52 weeks (364 days). Then, at the end of each year, there would be a one or two day public holiday. These days would not have dates or weekdays assigned to them, and would not be part of any month. That way, every year would be identical, so you’d only need one calendar. In fact, since every month would be identical, you’d only need one 30 day calendar.
This situation is easy to fix. Change the calendar so there are 13 months with exactly 4 weeks in each month, for a total of 52 weeks (364 days). Then, at the end of each year, there would be a one or two day public holiday. These days would not have dates or weekdays assigned to them, and would not be part of any month. That way, every year would be identical, so you’d only need one calendar. In fact, since every month would be identical, you’d only need one 30 day calendar.