There was certainly a Money 2004 North American version -- one of three versions. Since you were having a problem with Sunset trying to read your file, I suspected you had a UK or rest-of-world version (which I now know you don't.)
Do you have the Money 2004 disk? You could try installing that on Win 11. It may have some advantages over Money Sunset because it was made to be more independent. Its Help works better, for example. It does lack my favorite feature of Sunset -- the automatic multiple backups with timestamps incorporated in the *.mbf filenames.
Yet you should also be able to install Money Plus Deluxe Sunset, apply the patch, and open the old *.mbf file.
Do not put the *.mny file into your Program Files (x86) folder, but instead put it into your Documents or a folder within Documents. I have a folder named MN in my documents folder.
When Sunset goes to convert your Money 2004 file, it will save your 2004 file in a copy with a *.m12 extension.