I tried
x11/lumina around 6.0. At that time it reliably left a fluxbox.core at each login and used about 2x the resources. One of the integrated applications in lumina was for management of the zfs filesystem - great if you're running zfs in FreeBSD, otherwise just useless bloat.
There are a number of qt based lumina applications that have not been ported to OpenBSD:
Freshports lumina search