Swannone devices are zigbee, not Z wave. Nothing you can do about that, it’s a completely different protocol.
The zigbee standard allows for different “profiles” including manufacturer proprietary. These cannot all talk to each other, they don’t even use the same addressing standard.
SmartThings uses the “zigbee home automation” profile (ZHA 1.2) Devices that use exactly that profile can typically be made to work with SmartThings, although they may require custom code.
Devices which use other zigbee profiles either won’t pair with SmartThings at all, or may pair just as a generic thing and be unusable, or may pair but keep disconnecting from the network.
In the case of swann, a few of their devices do use the ZHA profile, and those will work with SmartThings. But many of them appear to be using a manufacturer proprietary zigbee profile, and just won’t work with SmartThings. 