How to generate/keep responsive images when moving/copying media

[LowSociety]

I have an app where users can upload images in a form. When an image is added to the form, it is instantly uploaded and added to a temp collection tied to that user. When the form is submitted the media is moved to the model associated with the form. I do this with the move method on the media. Now I want the new media to include responsive images but I can't seem to find a way to generate them, since I don't have access to the FileAdder instance created internally in the copy method of the Media model. Is there another way? Note that I don't want to generate responsive images on a conversion, so registerMediaConversions on the new model is not an option.

Looking at the copy method I'm wondering if it shouldn't generate/copy the responsive images if the original model hasResponsiveImages?