I believe one's view of what a dystopia and utopia is is very likely based on your frame of reference. In the original story the concept of Utopia came from, there was slavery. Not just in the fringes, no, there were literally two slaves in every house, and they included criminals and people taken from other countries. Anyone who came to the island of Utopia without having a passport given by Utopia is deported, sex before marriage leads to being forced to be celibate for life, and if you come back to Utopia a second time without a passport or if you have sex with someone else after marriage, you get enslaved. In addition, atheists were shunned, not sent away but largely argued against by everyone else there. It is unknown whether the writer, Thomas More, actually believes Utopia to be good or bad, or which aspects he actually liked, but regardless, the original Utopia was filled with flaws and issues.
The point is, from the perspective of many, this society would be extremely oppressive. Perhaps even to the point of dystopia. So what about the TiTS setting? Well, it is somewhat hard to argue about that, considering there are many different societies and governments which can form their own laws, along with the UGC being a major space government and the corporations being their own miniature space governments (due to how much power and reach they have).
But we can look at what we do have/know to talk about it: Entire races and cultures are exploited and oppressed (like that one race which the gallotians pretty much instantly tried to oppress into the ground because they were afraid of having competition for being the dick sucking race), and even aside from that, many people get forced into debt slavery where their owners then do several things to drive them much further in-debt to forcefully keep them theirs. Like how Reaha was apparently getting pumped with an aphrodisiac, which got her addicted and apparently cost enough that she couldn't work off her debt until after the player buys her and helps her work the addiction. Another example is, I believe, one character who was orphaned as a very young child. She was brought into a Snuglee orphanage (that corporation being the same one as the plantation on M'henga), and once she reached adulthood, they tried to force her into becoming a slave at a Snuglee workplace, because they could then enact the cycle of debtbuilding on her to keep her there, but instead she escaped, became a mercenary, and then paid them off for the debt she'd accrued as an orphan at their orphanage so they couldn't legally chase her down and recapture her.
I would argue that, to call the universe of TiTS a dystopia, you'd have to personally define a dystopia. In addition, you'd need to look at it from a reference frame. Utopias and dystopias are part of the same coin. Reaha and the character who's name I forgot were kept as slaves, and any society with slavery will almost certainly appear dystopian and oppressive to the majority of those slaves, for pretty obvious reasons. For those at the top, people like Beth or the owners of Snuglee, it's very likely the opposite case, as they get luxuries and more money than anyone could hope to use. For those at the top, the society where they get to remain at the top is their Utopia.
Also, aside from that. There's certain case-by-case planets where they may be judged separately. New Texas is a utopia for those who want the Treatment, who enjoy the sexuality of the place. But the thing is, The Treatment is illegal everywhere else for a reason. Despite how they were raised in this society, many of them were likely largely different people before the treatment came along and completely messed up their heads. They were effectively brainwashed into being one of the perfect citizens of this country. Reaha straight up had to leave the planet to avoid being forced to take a life-altering drug, because that was a requirement of its citizens. So, a utopia for those who like it, a dystopia for those who don't.
