we haven't had the "Let's Insert Slavery!" bit to this particular isekai series yet, so "why not", I guess
There's probably slavery , sorry... "indentured labour", in that world. That
was the most common form, actually, and a practical way to deal with criminals ( not outlaws....)
It just isn't something relevant to what basically is an extended Otome Storyline/Slow Life Story.
For this type of stories it'd be.. exploitive orphanages, corrupt officials, and
maybe a Perverted Noble.
Possibly an Evil Cult.
Maybe a "Become a ( Substitute) Teacher" arc.
Y'know ... Wholesome Stuff to let the totally-not-Slow-Romance simmer on Low.
(Yes.. I know the now-Crown Prince has his share of Haters. But the situation he's in both trying to Respect the FL and figure out a Solution for the Kingdom and his obvious Interest in her is one you don't often see... )