According to my communications with the US copyright office, you never get a global copyright by editing. At best you get a copyright on your changes - and that only if they are copywritable on their own. Minor changes to wording or tweaking an image would generally not pass that threshold. It is a case by case judgment as to the status of any individual change.
This is backed up by how they have granted copyright to an AI generated and human edited book. The human only gets to get copyright on the parts they "significantly altered".
There was a news report on it awhile back that was interesting to read.
