https://lists.qt-project.org/pipermail/development/2022-March/042262.html
This was so far commercially available but all opensource project e.g. KDE were parked at 5.15.2 due to licensing changes etc that QT has been going through. Yoe distro has QT5 reference image (yoe-qt5-image) as well which uses meta-qt5 layer to provide QT5 libraries were also stuck as 5.15.2, so perhaps soon we will get recipes upgrades in upcoming months.
There is a GH issue opened to upgrade to this version for meta-qt5