I am sur i have seen a smartapp to connect smartthings with the xiaomi mi home gateway.
I want to my xiaomi device were connected to the xiaomi gateway, and the xiaomi gateway connected to my smartthings hub.
I don’t want the xiaomi directly connected to my ST hub
There’s nothing that connects them directly. There are some community members using a raspberry pi or other device as a “man in the middle” server and getting connection to the Xiaomi cloud that way, but it’s a lot of work to set up.