🇩🇪Germany @Franz-m

In my case - D10.2.2 - I did not succeed. Hopefully this log can help ...

Gathering patches for dependencies. This might take a minute.
   - Installing drupal/core-recommended (10.2.2)
   - Applying patches for drupal/core-recommended
     3328277-ckeditor5-upload-image-2.patch (Cke5-Image-Upload)
 
 In RemoteFilesystem.php line 108:
                                                                                
   [TypeError]                                                                  
   Composer\Util\RemoteFilesystem::copy(): Argument #1 ($originUrl) must be of  
    type string, null given,

Franz-m → made their first commit to this issue’s fork.

ckeditor5 has fakeobjects as dependency.
But then, fakeobjects has ckeditor4 as dependency, so it automatically gets required on D10 on enabling footnotes :(.
As far as I remember, ckeditor5 possibly needs ckeditor4 to import earlier texts on migration.
Nevertheless, I edited fakeobjects dependency to drop ckeditor4. I'll see how my migrations (D6 .. D10) will do.