Why in the world would microsoft install onedrive my default, enable uploading by default, enable sync by default, and then not warn you that deleting files from the drive would also delete them from your system as well? This whole situation is asinine.
I can explain why Microsoft is doing this. In my opinion it is inexcusable.
The first time that Windows 11 sets itself up (or after a clean install) it does two things without informing you that cause mayhem among users.
First: It enables Bitlocker encryption. Many users have not heard of Bitlocker encryption and don't know what it does. They only find out about it after they are locked out of their own computer. Microsoft Community has many posts from people have been caught in this trap.
Second: The OneDrive app starts syncing and backing up your personal files. By now, many people understand what OneDrive is, but far fewer understand what syncing means and how it works. Microsoft Community is filled with anguished posts like yours from people whose personal files are all over the place or, even worse, gone!
Syncing means that the files on your hard drive and on your OneDrive will be the same. For example: If you add a file on your hard drive, it will also be added on your OneDrive. If you delete a file on your OneDrive, it will also be deleted on your hard drive. If you change a file in one place, the same change will be applied in the other place. Nobody needs to have the same files on their hard drive and on their OneDrive. Here is why Microsoft does it:
Microsoft's ultimate goal is for everyone to store their personal files on their OneDrive only, and not on their hard drive. (That's why it's called 'one drive'.) By attempting to maintain a mirror image of the files on their hard drive and on their OneDrive, Microsoft hopes to accustom users to storing their files on their OneDrive, and eventually to store their files on their OneDrive only.
There are definite advantages to storing your files in the cloud. Google has always worked this way. There are also certain disadvantages, but the pros and cons are beyond the scope of your question.
My point - my opinion - is that this method that Microsoft has chosen to 'persuade' users to store their files in their OneDrive is unacceptable and creates havoc among unsuspecting users.