With the new version 0.5.0 out, the problem with label.pad: none has been fixed. Also the built-in schoolbook theme lq.theme.schoolbook is now much nicer with axis labels.
Moreover, the field label.angle now defaults to auto (0° for x-labels and -90° for y-labels) which means that the angle can now be set to 0° through a “set” rule:
#show: lq.set-label(angle: 0deg)
which was previously impossible (one had to explicitly construct a lq.label(angle: 0deg)[y] instead of being able to pass just [y] and let set rules do the rest)!