I am looking for as hard science answers as possible, but I am willing to bend some rules for a good answer.
Assume they need to move 10 million 100 million people off of a planet
what technology should be used for an alien species to abduct around 50 million people to use as slaves?
This is for my own story, in which I once had the idea that an entire nation of millions (of an alien species, not humans specifically) were abducted, almost every single one of them, by outside extraterrestrials and taken to work as slaves, some of them as gas-giant miners/extractors on special stations built to mine gas-giants of whatever resources they have, but I was told by some people on the Worldbuilding subreddit's Discord that it would probably not be profitable for the aliens doing it. Especially as they'd need many people and possibly a lot of equipment and technology to get the slaves.
bonus question, I would be happy if you answered this but it is not obligatory: would this be profitable?