I think it should be legal, with extra protections for the workers to protect them from exploitation and abuse. Unfortunately though, our entire economic system is exploitative, so I’m not sure if it would ever entirely be by choice that somebody turned to prostitution, though labor itself is never entirely by choice. I only work at my job because I have to, not because I really want to. A worker selling their body to perform legal labor for money is on par with a person selling their body for another’s sexual gratification. Making it illegal just makes it worse for the workers, since they’re obviously going to do it anyways and won’t get any protections from the law.
Sex doesn’t always have to be for love, equating it with love is something religious people have forced on the world to get over their own religion-induced guilt over the whole thing. Bonobos have a crazy amount of sex and use it for all sorts of social interactions, it’s something animals do to feel good and relieve stress. There’s instances of other primates even engaging in prostitution as well, where they trade sex for food, and prostitution is one of, if not the oldest job among humans.