Installing from the raw.xz, instead of dropping the user into anaconda, to configure user/timezone/network, the LXQt raw.xz installer is taking you directly to sddm, where there is no user setup, so you can't actually do anything.
Tested on rPi400
Works fine on the Fedora-KDE raw.xz, so I know it's possible to do.
https://bugzilla.redhat.com/show_bug.cgi?id=2358688 is the bug filed against the XFCE spin for the same issue, I suspect that whatever fix they come up with is going to be similar, if not identical for LXQt
https://bugzilla.redhat.com/show_bug.cgi?id=2359195
LXQt specific bug.