it doesn't detect any wi-fi device on my laptop only the ethernet works
Which Plasma version and which NetworkManager version are you using? If unsure, ask in a forum of your distribution.
What is the output from "nmcli device status" and "nmcli device wifi"?
FWIW, given the original report was against the drivers KCM I'd expect the problem to be with https://bugs.launchpad.net/ubuntu/+source/ubuntu-drivers-common not detecting a proprietary device (or simply having no driver for it) rather than network-manager.
To further investigate this issue, KDE developers need the information requested in comment #1 and comment #2. If you can provide it, or need help with finding that information, please add a comment.
No response, changing status. If you have new information, please add a comment.
Bulk transfer as requested in T17796