I am not sure about IKEA Badring sensors, but about 50% of all of my devices connected to SmartThings are not compatible with Alexa, and just don’t show up. This includes every water leak sensor that I own, non of the devices allow for monitoring or control via Alexa.
To get around this limitation, I have added virtual devices in SmartThings that are Alexa compatible, and mirrored the virtual device from the state of the actual device. I usually just use a virtual Alexa switch, on for wet and off for dry, so Alexa can react and make announcements or whatever.
You may want to try creating a virtual Alexa Switch using the below driver and see if asking Alexa to “discover new devices” works to have it show up in Alexa. If that works, from there, you would need to use a Routine (or 2) or Smart Lighting (if available in your region) in SmartThings to mirror the state of your IKEA Badring sensors. The driver also has a virtual Water Sensor as an option, but I have not tested it with Alexa, so I recommend sticking with the virtual Alexa Switch at first.
Let us know if you have questions that aren’t answered in the vedge creator thread.