Just been playing with Sonoff Touch and Tasmota firmware and there is a device handler which directly integrates with smartthings. No delay like when using IFTTT.
Works perfectly but is is on the intermediate to advance in building… fiddly as hell!
Works a treat. if you can read the wiki (read carefully for your device as there are potential problems) and are confident with electronics, it’s the cheapest Wi-Fi switch solution I’ve used.