First time I hear that there's a good way of being a slave.
Well, there is a good way. It is called a consent based relationship. People willingly go into a contract fully informed, having negotiated terms and consenting to follow certain roles/rules. This types is not found in the black slave trade. It isn't found in the white human trafficking slave trade. It wasn't among white men who made slaves of indigenous people, though it was sometimes found among indigenous people who made slaves of white people or foreigners. It is found in the indentured servants of the 1800s England and America. It is found in ancient Rome, ancient Greece, and a whole bunch of different eras and societies. You just have to look a little harder for it. Even in this type of slavery, there are abusers and predators. That happens everywhere humans are. But you can find some amazing stories of real life atypical stories. You just have to look for them.
In ancient Rome, there were certain slave positions that were sought after and had an elevated status. Most people don't want to be slaves and that is when it is bad and wrong. But history is actually full of examples (rare though they may be) of people who actually went into slavery willingly. Slaves had something that some other people didn't have. They had a roof over their heads, fully bellies, and even protection from harm. If you had an owner that treated slaves well, if you have a higher status, etc. then slavery wasn't always the worst thing in the world.
There are also forms of prostitutes in some former societies that had a slave status which gave women certain freedoms. The Hetaera of ancient Greece were one of these. They were like really highly educated and high priced companions. They couldn't marry at the highest level of society but once they worked off their service term then they were able to work for themselves. They were highly educated and had a very high status in society. They were often able to own land, have their own slaves, hold positions in government, and had the ability to acquire large amounts of money. Their counterparts (free women of high social status/class) who were able to marry, had much more limited rights and were always under the thumb of their husbands or other male relatives.
So... yeah... there actually are good kinds of slavery.