I believe Qt6 is superior and more likely, in the undefined future, to cope with Wayland better than Qt5. But the differences now is not that great and more systems are likely to have the the LibQt5Pas installed.
But its so easy to produce either with just a recompile, why not make both Qt5 and Qt6 versions available ? Let the user (or the distro packager) make the decision ?
Looks like a great idea I must say, something badly lacking in the rpm world.
Davo