MS Acct vs Local acct

I suspect the calendar as well as some other Apps are tied to OneDrive and stuff like that has to be synchronized thru MS account because it's provided by them.

The calendar is an excellent example.

The way the Calendar app works in Windows 8 and later needs an account. It might be that you never need or want to share your calendar, you might never need a possibility to access it from any other device than your home PC, but, believe it or not, quite a many users (majority, in fact) need these features at least occasionally.

As I mentioned earlier, the local account in Windows 8 and later allows you to use your PC almost as if it were Windows 7. There are some changes which you either accept and adapt, or migrate to Mac or Linux. I mentioned earlier Windows Update being one of these changes, the Calendar is another. (By the way, migrating to Mac you need an Apple ID so if being against MS Account is the reason to migrate, Mac is not a viable option.)

If the MS Account really is so big devil that you really do not even consider using one, there's always other options. Type free Windows calendar to Bing and you can choose from a plethora of alternatives. Here a few samples: Five free but powerful desktop calendars - TechRepublic.

I am totally unable to see the issue here. It really is up to you, the user to decide. Accept and adapt the changes. Use new Windows with legacy type (yes, legacy!) user account if you are refusing to harness the full power of Windows, replace the apps needing an online account with desktop apps which do not require it. If even this is not for you, get a Mac if your budget allows and those with less to use, download a free Linux distro.

Or, if you really think it through and can finally understand that starting to use an MS Account does not mean your PC is constantly calling home telling your every keystroke, be clever and sign up for an MS Account if you don't already have one. Using your existing third party email address to create the MS Account, you will never ever get a single email to the inbox of the MS Account, you continue using your 3rd party email as before. You don't have to use that account in any other place than just signing in to your PC.

Did I forget to mention that not only do you get the fine Calendar app working, but also free OneDrive storage plus Excel, PowerPoint and Word for free (online versions)?