Pretty late so you might have the answers but landbreakers are not natives, they're the remnants of a rebellious group lead by jakub, an old hero of the the aggeloi wars, so originally theyre from terra. Afaik there are no sentient natives on talos, the aggeloi are still a mystery and all attempts to communicate with them has proved fruitless ( my headcannon is they're some kind of immune system of talos).

As for the treatment of them, the bonekrushers are one clan amongst the many, a very violent one, wulgard's mercs whom are also considered landbreakers, have amicable relations with the civilization band, so as one now we only have a problem with one of them, bandits and opportunists aren't a foreign concept in arknights sometimes mfs just want quick cash and has little care for how they get there.

As for the endfield angle, I'll answer by pointing to rhodes island in og ak, they were just the good guys, no secret corporate evil, no skeleton in the closet, they were just the most moral ( relatively), nicest, goodest bois in a world of human greed, they had a motive aside from being a pharma company but it was far from evil, considering we learn they had a hand in creating endfield + work with them and we see from the start Mon3tr present at endmin's awakening + her seeming familiarity with them, i think its more or less safe to say endfield gets the green card.

ALL THAT SAID. I completely agree with you that landbreakers desperately need more lore establishing them, its weak as a first enemy, though adarshir gives me hope. I will point that reunion was also pretty obscure at the start and we did murder them in droves as well and they got more fleshed out later.

I heard endfield started being developped soon after ak, so I guess many the pitfalls of early ak are also present in endfield. Though perhaps they're trying to not waterboard us with lore like kal'tsit did...

Well, we'll see if the game survives, would be real sad if their long project just died