If they're LED I have just used units that fit behind a retractive switch, within the back box, and they make two gang units of the same physical size. Look for Moesgo on Amazon. They're a doddle to wire but you will need to change your switch and you will need a neutral.
These are rare, most that do exist work using a hub which converts your wifi signal to RF. So the switch is actually RF based. If they do exist, I haven't found any.
Alexa acts as the hub, or an app on a phone, for more and more units as hubs are seen as expensive lock-ins these days. I don't think it was the RF that was the issue, rather the brand.
Ah yeah that would be fine too - this is how lightwaveRF works, but I am just looking for a cheaper alternative
Hence I haven't committed to any of the hub based wifi products. I use Google and would like to make some of the dimming lights smart, thugh it's easily done using apps, I need the wall dimmer to work as normal or the wife isn't happy. I buy my smart products based on "works with Google" and no hub required. I think I might have to bend the rule on some electric blinds I've recently fitted, but begrudge paying SOMFY £250 for a hub to make them work with google; I think the product is zigbee based but I haven't found anything on the net to make them work using a cheaper hub.
I can see a 2 gang Moesgo switch, but only a 1 gang dimmer. How does it work? Is there a special retractive switch that goes with it?
If you don't mind the wifi>RF conversion, have a look at a company called Hartingtonheath, they have some products but I haven't used them myself. Much cheaper than Lightwave
They are based in Bounds Green London, I went to their offices but their showroom wasn't set up and I didn't have time to wait for them to rig a demonstration up for me. I wanted to see the lag between command and the lights working.
https://www.amazon.co.uk/Dciustfhe-...+gang+wifi+dimmer&qid=1612434940&s=diy&sr=1-4 Not the Moesgo brand but, essentially, the same thing. Any retractive switch should work. Holding the switch will adjust the brightness. I have three single gangs for my kitchen/diner They are mounted in the larder and just have a single three gang retractive to operate them when not using voice.