Timers are available today on ESPHome and Wyoming voice satellites that are connected to the latest version of Home Assistant. If you use the firmware we provided for the Atom Echo Dev Kit or the ESP32-S3 Box 3, update to the latest version for timer support.
https://www.home-assistant.io/blog/2024/06/26/voice-chapter-7/#timers-are-here
Adding this functionality would make life easier and would allow for using built in HA functionality which will probably be supported better than homebrewed code (eg View Assist timers blueprint).