For a completely different approach which uses a small robot finger to just push the button and won’t void the warranty on the coffeemaker, you can take a look at the Naran Prota Devices.
These work well (I use one on a blender at my house), but the problem is they are expensive. The individual microbots list at $49 each, although sometimes they’re on sale for less.
They connect via Bluetooth, but then to get smartthings integration you need something that will act as a Wi-Fi bridge to get to their IFTTT channel.
The company offers the bridge code for free if you want to download it onto a raspberry pi.
Otherwise you can buy a “Prota” bridge device from them for about $80 which can support up to 40 of the microbots. I bought the bridge.
Amazon reviews are all over the place because this is been a rapidly evolving product and there’s been a bit of complexity and getting it set up initially. But after that it seems to work pretty well. So just another possibility. 