@Oranjoose - Are you a programmer? Have any experience with simple, low voltage electronics?
If so, you could try using my ST_Anything project, as it allows for a simple ESP8266 or ESP32 device to be easily integrated with SmartThings. ST_Anything can easily control the output of a relay, handling the timing locally on the microcontroller.
The only concern I have is that ST_Anything is very much dependent on the legacy Groovy IDE for its DTHs. Once Samsung shuts the Groovy IDE down, ST_Anything will cease to function. I migrated over to Hubitat 3.5+ years ago, and that is where my development and support is now focused.
I think the Zooz solution is probably the simplest, and probably lowest cost option. As long as it handles the relay on-duration timing locally, it would be a very good solution.