This WiFi device is available in both the US and the UK. It lists for around $45 but is sometimes on sale with a coupon for five or $10 less.
US:
https://www.amazon.com/gp/product/B08CKGXVL3/
UK:
It works out of the box, no custom code needed, simultaneously with SmartThings, Alexa, and HomeKit, although slightly different features are available with each.
It has a tap control on the top which allows you to turn it on, off, dim, or change the colors, which is very convenient.
It’s advertised as 40 lm, but I think it may even be a little brighter. Certainly good for notifications or as a nightlight.
Colors are distinct and white can be changed from cool to warm.
Now as far as what you can do with the different interfaces…
SmartThings
White Color Temperature
You have full control of the color temperature using sliders and can set that in a scene.
Dim level is a separate variable that can be set in the same scene.
So it’s good on the setting side.
However, unlike most platforms, there’s no indicator in the app to tell you that a scene is active. So you may want to add an additional virtual switch just so you can tell which scenes are on.
RGB Color
Color basically works the same way as RGB color. Again, there’s no visual indicator to quickly see what it’s currently set to in the app. So if you change the color through one of the other methods, you probably have to look at the lamp itself, not just at the app.
Changes made through scenes do not show up in the list of recent colors.
The lamp was just set to Green with a SmartThings scene. You can see that it’s on, but there’s no way to tell that it’s green.
Alexa
white color temperature
You can set the white color temperature by voice and Alexa is really good about asking for clarification. So if you say “medium“ it will ask you what you mean by medium and then save that for future use if you want it to.
If you look at the detail screen in the Alexa app you will see an indication of the settings.
However, even though you can set these values with Alexa and they will show on the detail screen in the app, you can’t ask Alexa what the current settings are.
RGB Colors
These work the same way as color temperature. You can set them by voice and you can check the current status in the app, but you can’t ask by voice for what the current settings are.
HomeKit
White color temperature
Not currently available in HomeKit. Meross says they will add it as soon as HomeKit does, but for now you have to use the Meross app to set color temperature or one of the other integrations.
RGB colors
You can see the current settings on the detail screen in the app:
And… you can ask Siri what color the lamp is currently.
So I imagine you are using this as an “on the air“ notification light for zoom meetings, and it’s sitting on a little table right outside that room.
With Homekit, you could also be in the kitchen and ask what color the attention light is and it will tell you “looks like Red to me.“ so now you know the other person is busy without even having to get close enough to see the lamp. This is also helpful if you have one person in the household who is colorblind.
Also, the Homekit status is updated no matter what method you used to change the lamp.
Summary
This device works well for notifications no matter which of these three platforms you are using, or if you are using a combination of them. And it’s priced really well, particularly since you won’t need a Switch to keep guests or kids from turning the power off.
The fact that it works with smartthings without requiring any custom code is another plus. 
The adjustable color temperature is nice if you want to use it as a night light.
And the tap control feature on the top of it is really nice.
That said, it does have some limitations on every platform. Not being able to see the current color in the smartthings app is a definite limitation. Not being able to ask Alexa for the status is also a limitation. it works well with Homekit for RGB, including asking for status or viewing it in the app, but you can’t set color temperature at all through the Apple home app.
And one limitation even with its own app is that it can take Meross is 20 or 30 minutes to update its own database when you first add the device. (There is a note about this in the Meross app.) So it can take a while to Show as available even in its own app. The only app which picks it up immediately is HomeKit, which makes sense, because that is a local system, it’s not using the Meross cloud.
Anyway, after it shows up in its own system, then it can take another hour or so before it shows up in Alexa or SmartThings. But once it does everything works fine. You just have to have patience during the setup process.
If you use smartthings, this is really easy to automate for different RGB colors or white Color temperature Using smartthings scenes. But you may want to set up an additional virtual switch as a proxy so you know what scene is currently turned on.
