KDE is okay out of the box, there are like 5 things I normally change from the defaults. It has tons of powerful apps (unlike GNOME?) Like KDENLive, Kate, etc.
GNOME on the other hand has tons of circle apps, with GIMP and Inkscape being the big players.
Of my messages and contact numbers? Not doing that
But its easy to find, just click the 3 bars next to the connected device and select SMS messages. KDE connect requires the app installed on the device to pair