The CPP export campaign logic refactoring is done in PLANET-4456 [https://github.com/greenpeace/planet4-master-theme/pull/995/files] (remove regex logic and use parse_blocks() function to extract image ids from Gutenberg blocks),

Similar code refactoring needed in import campaign functionality(https://github.com/greenpeace/planet4-master-theme/blob/develop/classes/class-p4-campaign-importer.php#L39)