While your Tuya Smoke Detector might not show up as a trigger in Alexa most Tuya switches, plugs and bulbs do. The list of Tuya Alexa triggers is actually much better that SmartThings.
So you could add a cheap Tuya WiFi plug to your Tuya account and then create a Tuya automation to turn on the plug when smoke is detected. Then you can use that Tuya plug in Alexa to trigger an Alexa routine to say FIRE or whatever you want. This will NOT involve the use of SmartThings in any way.
You can create Virtual Devices in Tuya. The process is different and more difficult than creating a SmartThings virtual device. 1st you need to create a free Tuya developer’s account and then log into that account using a web browser to create the virtual devices.
There are many choices of devices to create. The virtual devices are actually copies of physical Tuya devices. You can only make one copy of each device, but this is not a problem since there are many choices.
Some of these virtual devices have Alexa and Google integrations, and a few actually have SmartThings integrations. Unfortunately many of the SmartThings interactions are one way. One of the Brazilian power strips gives you 5 or 6 virtual switches that actually show up in SmartThings.
See the following links for instructions.