I've heard later macOS versions (Big Sur 11.0) have issues with RPG Maker MV games. See https://www.rpgmakerweb.com/blog/regarding-future-rpg-maker-mv-macos-support Maybe that could explain some issues.
RPG Maker MZ could be a workaround for macOS, but it would take a lot of work to get Didnapper 2 to work on MZ since the game uses plugins which don't work on MZ. Theoretically, FOSSIL (for MV plugins) and the VS plugins (to replace the YEP plugins) could be used, but Events would need to be redone due to code differences between the YEP and VS plugins.