Getting start with Rider and Unity

Greetings

I'm following a course about Unity. Of course the instructor says to use microsoft visual code but of course I'd prefer to use JetBrains' products which I'm used to and love.

I've followed the very short indications here: https://www.jetbrains.com/help/rider/Unity.html

I have the green "connected" checkbox, but no completion or proper syntax coloring. What am I doing wrong?

I'm using Ubuntu and the latest version of Rider and Unity I downloaded two days ago.

Thanks in advance

Regards