Qt4 support in 2022?

Are we still serious about keeping BUILD_KF5 cmake option in a time when packages are ported to Qt6?

Even dependency on kdelibs4support increasingly becomes an oddity now: https://qa-reports.gentoo.org/output/genrdeps/rindex/kde-frameworks/kdelibs4support

(some) porting work was lost in 967358b9 and 0d02e928