The .desktop file can associate with .exe files for example.

It would be nice this tool could be extended to additionally generate launchers for wine (Windows) .exe files and the icon selection would allow the selection of .ico files (which can be converted to .PNG by imagemagik)

wrestool --extract --output=. --type=14 --name=100 ./app.exe
convert app.exe_14_100.ico app.png

See /usr/share/doc/wine/examples/wine.desktop for possible file associations.

Similar project that may serve as good reference material

https://github.com/konarev/wine-launcher-creator (dated.. uses Qt)
https://pypi.org/project/desktop-file/