You're a little over the top in your concern, but not totally without justification. Microsoft wants everybody to use a Microsoft account, so they think up lots of ways to persuade or simply trick you into using a Microsoft account instead of a local account.
But you don't have to worry. I also use a local account and have no trouble downloading from Windows Store.
Understand that everyone needs to have a Microsoft account, but you never need to use your Microsoft account, unless you want to. By that I mean that you never have to sign in to your Windows PC with your Microsoft account, unless you want to. You can use a local account if that's what you want to do.
You need to have a Microsoft account because you'll need your Microsoft account's username and password to take advantage of virtually all of Microsoft's online services, like OneDrive, Outlook.com, Xbox ... and Windows Store.
When you open Windows Store from your local account you will, most likely, be 'encouraged' to convert your local account to a Microsoft account. But you can refuse. In that case you'll be asked for your Microsoft account username and password. Once you've entered them, Windows Store is yours and you've still got a local account.