If you formatted all the disk again, is gone.
If you deleted only the Windows system, most of your hard disk is just inaccessible, but files will be there still for a while until overwritten by new files. The more you will use the computer from now on, the more old files will disappear, but some (or most), could be still recoverable.
I could be wrong. I'm not familiar with what changed on Win 11 or NT File System, but if the personal files were important, it may deserve a try.
If you deleted only the Windows system, most of your hard disk is just inaccessible, but files will be there still for a while until overwritten by new files. The more you will use the computer from now on, the more old files will disappear, but some (or most), could be still recoverable.
I could be wrong. I'm not familiar with what changed on Win 11 or NT File System, but if the personal files were important, it may deserve a try.