deepin has its own desktop environment (DDE), so the only outside authority would be from experimenters adapting it to their own distros. deepin is also designed to offer a nice selection of alternatives to relatively new users, so I wouldn't expect to find many custom mixing opportunities. I know of no way to do what you suggest, but icon size is certainly defined somewhere - it could be the window manager or even file manager. If there is an easy way to change this, hopefully this posting will attract the attention of someone with specific expertise. As to amateur approaches - higher resolutions make icons smaller. Perhaps you could play with this and find something satisfactory.