How do you write a brutal dictator to not be "big bad", but relatable, despite their crimes?

I am writing a fictional universe for a game and its a power struggle between the humans and vastly technologically superior aliens. The only hand the humans have is that they're willing to use any and all tactics available to even the odds, including apocalyptic levels of destruction to themselves and their colonies to wipe out the aliens.

Here's the problem. The Dictator makes those decisions, supposedly killing some to save everyone else. I want to be clear, that the Dictator cares about human lives but not the aliens', a contrast to the hero, who cares about all beings. However does he really care about human lives if he's willing to sacrifice them just like that? At the end of the day he's ordering people's deaths, without harming himself or his position of power. To make such decisions and be a dictator, you should have inherently have a scewed moral code, making you a "big bad evil" guy, which i dont want. And I want to avoid the "mad with power" trope as much as possible.

What needs to change?