Windows 10: Suddenly I found a weird border in all the applications

Dear Support Team,Kindly i need your immediate support as suddenly I found a weird border in all the applications in the windows. I have Windows 10 Enterprise version 21H1. I need it to be removed or to be thin like before. Examples of the border:

:)

 

Weird Windows 10 Border

We appreciate your response. One of the possible reasons why you’re experiencing this issue is system file corruption. Before we proceed, we would like to confirm if the issue is happening to all applications or to a specific application only.

In the meantime, we suggest creating a Test User Profile.
This is for us to know if the issue is not with your existing User Profile. To create a user profile, follow these steps:

• Go to Settings.
• Click Accounts.
• Select Family & other people.
• Select the Add someone else to this PC tab.
• Name the user as Test.
• Set up a password.
• Hit Next.
• Sign in as Test user.
• Check if you’re experiencing the same issue.

Hope to hear from you soon.

 

idm Border Problem . windows 10

Is it just that application? Do the weird borders affect other applications?

 

Weird border with the exit, minimize, and restore down buttons windows 10.

On some of my apps, there is a weird gray border around my applications, however the border disappears. However, the minimize, close buttons look weird. They are really thick, instead of the ususal thin black. The first images appears on only Winows system
apps(?)(taken from file explorer). Settings has the weird gray border around it.