If we’re still talking about the use case from post one, and by “controller” you mean something to control LED lights,
I have a very simple SmartThings automation rule which turns a device on/off whenever another device is turned on/off. The master device is a hard wired (mains) Kasa switch and the slave is a generic 12V LED lighting controller(Tuya). Both devices are connected to ST by linking their respective accounts to ST.
.
My problem is that there’s a substantial delay in turning on the 12V controller, something like 2s, might not seem like a lot but these different devices are in close physical proximity so it feels very weird to have them come in sequence and not simultaneously.
Then Shelly offers some UL listed Wi-Fi options that should meet your description.
The standard integration is cloud to cloud, so two seconds would be considered an acceptable response time in the industry. But I do understand how annoying the “popcorn effect” can be when multiple lights in a room come on separately.
As we mentioned upthread, there is a community built Shelly integration which runs on the local LAN, but you will have to have A SmartThings compatible hub to run the edge driver for that. You can ask more questions, and get configuration requirements in the author thread for that edge driver:
Edge Shelly drivers for Gen1 and Gen2 Devices
As for other “reputable“ LED controllers, you’re probably just not familiar with the names since they are usually big Chinese companies. But there are quite a few of them, including Gledopto.
And of course, Tuya is one of the largest Home Automation companies in the world. (If a device works with the smart life app, it’s likely it was originally made by Tuya and is rebranded by another company.) you can get local integration with many of their Zigbee devices, but it does get tricky as they use a lot of proprietary code. And definitely not UL listed, this is a budget brand. So I don’t know if you want to go further down that particular path, but there’s a ton of forum discussion about those devices.
Have you had a chance to look at the community FAQ on LED strips?