Are there any complex life forms that don’t hunt, or cause harm to organisms in their environment? Plants..? Sea slime?
It is not a realistic understanding of systems. I would suggest reaching out to an ecologist, or if you want someone to relate it to humans, somebody in "social ecology"
In before "Google Bookchin"
That aside, there is no collaboration without competition, there is no peace without conflicts and vice versa.
This is how living systems evolve.
Digging deeper you’ll find that our world is inherently dual.
And people just follow natural tendencies and reflect that fact like any other system.
But sometimes on a much higher scale (just like we produce energy or food on same high scale).
bacteria, funguses and such also try to poison other species, sometimes even their own conspecifics.
The standard model of population growth is exponential at short time but flattens out because of resource competition -- so I'd say even the simplest life forms do some kind of harm.
This is why they were revered in ancient Greece, Persia and India -- as a mental model for how to develop symbiotic relationships and do trade instead of pillaging other communities.
Humans inflict a toll, but we also can do a lot of stewardship. Probably this kind of existential crisis is why so many religions do things like give thanks for food before eating (because food comes from other living things -- we don't eat rocks).
I think one would be hard pressed to find a purely beneficial species that doesn't harm another. Especially if you consider competing over resources as harm.
Nothing survives that doesn't have some kind of survival instinct and some means to protect itself when threatened.
Mobility also needs to increase to avoid conflicts which lead to physical harm.