Microsoft used to have macro-enabled templates that let you set the year or month and have the dates adjust. They have stopped offering those, perhaps because people were afraid of the macros.
If you have used a macro-enabled template from Microsoft in the past for this, it should still be on your computer in the folder you have designated for saving custom office templates. Such a template would have the Calendar tab.
When you use one of the templates from Microsoft, it is stored there.
I expect that sometime in January Microsoft will come out with 2026 calendars. This is based on experience since they discontinued the macro-enabled calendar templates.
You can use the free calendar add-in from former Word MVP Greg Maxey that you can download from here: https://gregmaxey.com/word_tip_pages/calendar_maker_addin.html
You can also find free 2026 calendars on MVP Jay Freedman's download site. (https://jay-freedman.info/)
You can find a free perpetuaal calendar maker add-in on MVP Graham Mayor's site.
No one here can change how word works.
No one who can change Word sees what is written here.
This is a user-to-user forum. You are corresponding with your fellow users. We can tell you how to better use Word as it is.
People who can change Word never see what is posted here. To get their attention, use the Feedback mechanisms. Here is more information about how to do that and what to expect.
Here is a link to some of the feedback:
https://feedbackportal.microsoft.com/feedback/search/fb6d67e3-301c-ec11-b6e7-0022481f8472?q=calendar
You can comment and vote if you want. I do not expect this to change. I recommend using the items from Jay Freedman, Greg Maxey, or Graham Mayor.