Fan control - is it motor or just dry contact

For Multi speed fan control, or any variable motor, you need a switch specifically designed for motors because the physics are different than a normal on/off switch. Specifically, you tend to get a very very high power spike right at the beginning when the device is turned on and that can literally burn out an ordinary light switch.

If the fan is just a simple on/off fan, like the exhaust fans in some bathrooms or kitchens, then you just need to match the amperage.

There are several devices available for Multi speed fan control That work well with smartthings. See the community FAQ. Although the thread title mentions Alexa, you use the same devices whether you are going to use a voice assistant or Not

FAQ: 2020 Ceiling Fan and Dimmer light wall mount control compatible with SmartThings and Alexa?