There are several ways to go about it.
Personally, I went the other direction and installed Fedora on a separate SSD after Windows 11 was installed.
As has been noted, it’s absolutely doable, although you might want to consider using a Windows 11 VM instead. Alternatively, you might try using Wine.
If a VM or Wine are not desired options, there are some issues with installing Windows after Fedora that are addressed here
Please let us know if you’re having issues or need help with the suggestions (by me or others) and we’ll see what we can do.