Only a few smart life compatible devices are eligible for transfer to SmartThings. You have to look at each device in the Smart life app to see if it has a SmartThings option. Most of them will not.
If it’s an on/off device, many people use “tap to run“ scenes created in the Smart Life app as an alternative way of getting integration.
Here’s an FAQ explaining that method:
FAQ: How does TuyaSmart Integration work? [Updated 2023]
If your devices are Zigbee sensors, you might be able to use the matter over bridge method, but so far that only works with a few models.
So…
What are the specific brand/model devices you were hoping to bring over? 