It is possible that your System Updater has got stuck a bit like reported here, Issues with the Updater and a solution. You might try that before anything. Should that not liberate the following updates, you could just take that one. Maybe that update will liberate following updates. Release notes for 1.21.1 v1.21.1-s · e / os / 🚀 Releases · GitLab mention work being done on Recovery.
Check if the updater can do a Local update, top right menu. Then you can put the ROM on the phone or SD card, navigate to it after tapping Local Update and you are away.
Be sure to check whether your emerald is running stable or dev Different Build Types so that you avoid accidentally “changing”.