I would suggest that this --curation in general, not just images-- is a mistake and, ultimately, wasted effort. Roon’s forerunner, Sooloos, became de facto curation software (for a variety of reasons), but Roon is not and was never conceived as a curation tool.
We have always regarded editing features in Roon as there for minor correction purposes only, not wholesale curation. If you use it for curation, you will always be fighting “the system” to a greater or lesser extent.
Although we will always honor edits where the edited objects still exist in your library --a Cloud-side merge might make something locally with an edit vanish-- we reserve the right to make changes to product and metadata at any time; and any such change could break the curation scheme you are using.