No, I only have to re-authenticate my Alexa login in Home Assistant maybe about once a month, if that. But I’m using Home Assistant and a HACS add-on called Alexa Media player- GitHub - custom-components/alexa_media_player: This is a custom component to allow control of Amazon Alexa devices in Home Assistant using the unofficial Alexa API.. With that setup, the Alexa devices all are entities in Home Assistant. With the Home Assistant Smartthings integration - SmartThings - Home Assistant all my Smartthings devices are also entities in Home Assistant. So after all that is setup (which was quite the process), node red controls the Home Assistant devices using this palette node-red-contrib-home-assistant-websocket (node) - Node-RED and can do announcements with a properly formatted JSON.
It works well and reliably, but took a lot of steps to setup. Your method is fewer steps to get going but if the login has to be re-validated every week that would be a deal breaker for me. Here’s an example in the Alexa Media player WIKI Examples: NodeRed · custom-components/alexa_media_player Wiki · GitHub