On overviewPage I found it sufficient being empty, since the title is directly above it, anyway. But in the channel itself it looked wrong without a user name.
The name link doesn't have a href – this would only be useful for edge cases like someone sharing a "changed title" message to another chat. I did not consider that relevant enough.
https://doc.qt.io/archives/qt-5.6/qtquick-performance.html
In general, "property var" should be considered to be superior to "property variant" for every use-case from QtQuick 2.0 and newer (note that "property variant" is marked as obsolete), as it allows a true JavaScript reference to be stored (which can reduce the number of conversions required in certain expressions).