Patents are not invented by themselves, or the existing forms are invented and created by themselves.
Looking at your question again, do you feel that you have added a lot of knowledge to your calendar that you think is very practical for people? First of all, calendars are not inventions, and practical things on calendars should also be everyone's social achievements. Your contribution is to combine them, so you can't apply for a patent, but you have copyright. There is no patent for writing a book, but the copyright is inviolable.
You can take the initiative to contact the publishing house and send them a manuscript. Some publishing houses may not attach importance to it, but it doesn't mean that your work is worthless. Bole is good, it can be as good as a few.
Don't worry about some publishers returning your manuscript and then adapting it for publication. In that case, you can sue them, as long as they are similar to yours, you can sue and demand compensation.