But seriously now, looking from other modern pdx games, authoritarian nations will be the best, specially with slavery and all dependents working.
Slavery and serfdom will be good, because are free RGO production. Depending how enslavement will be, like conquering and displacing unaccepted cultures, this will be even better.
Child labor too, it decreases pop growth and literacy, but again, will be possible to stack modifiers to make it profitable and better in long term.
Women labor will be a must, to increase even more profitability (decreasing unrest too !!!).
Will people get upset? Of course, but considering how revolts are underwhelming in EU4, Hoi4 and Stellaris, due mechanics and modifiers, is safe to say that they will be underwhelming here too (compared to Vic2). Vic2 systems are before EU4 ones, were rng based.
Again, if your empire is rich and people are getting their bread and circus, everything is fine. So authoritarian countries will be viable too.