Good news, my friends: Starfield players have entirely abandoned human morality in their quest to invent the most effective methods of XP grinding possible, turning the game's rambling planetary plains into a kind of Victorian safari hunt. I'm discomfited, disturbed, and would quite like to unlock the manipulation ability, so might give this a try myself.
Over on Reddit, players have identified two excellent spots for XP farming from Starfield's many, many planets. The first is Schrodinger III, pointed out by Canatee on Reddit, where you can travel to obtain scads of XP if you're not particularly keen on animals.
I mean, hey, it works. At around 500 XP a pop, it's not a bad return on your time investment given that all you have to do is camp out atop your ship and make light work of all creatures great and small. I admit, I've tried to do something similar myself in Starfield whenever I wanted to quickly level up, but I never found anywhere quite as fauna-filled as Schrodinger. You can find the planet, appropriately, in the Schrodinger system.
And if you've truly no respect for nature, Canatee's offering was one-upped by a similar suggestion from a player named 1Bot2BotRedBotBluBot, who offered the Celebrai system's Celebrai II as an even more lucrative option for avid hunters. Just tool yourself up with a grenade launcher and wade into a thicket of Flocking Roundshell Grazers, who have a tendency—as the name suggests—to all stick together in easily-explodable clumps. Delightful!
So yeah, that's terrible. Give it a try, why don't you? You can tuck a whole bunch of levels under your belt and join players like CarsonFoles, who says "even in a video game...this feels wrong," or garyll19, who tried it out themself but "started feeling guilty after a while," noting that "It doesn't help that they make such sad noises as they die and look so innocent when they're dead." Ever the innovator, garyll19 did suggest it "Might be easier if we had a laser weapon that just immediately vaporizes them." It's that kind of human ingenuity that put us in space in the first place.