Fine tuning for the earth might be able to be explained away most easily, like you said. Fine tuning for the universe, though...

Firstly, we have zero evidence for multiverse. Some scientists even argue that the idea is untestable and unfalsifiable.

When you said:

> there must be a graveyard of universes where the parameters just didn't work out for life

You just committed inverse gambler's fallacy. It's like:

> You wake up with amnesia, with no clue as to how you got where you are. In front of you is a monkey bashing away on a typewriter, writing perfect English. This clearly requires explanation. You might think: “Maybe I’m dreaming … maybe this is a trained monkey … maybe it’s a robot.” What you would not think is “There must be lots of other monkeys around here, mostly writing nonsense.” You wouldn’t think this because what needs explaining is why this monkey—the only one you’ve actually observed—is writing English, and postulating other monkeys doesn’t explain what this monkey is doing.

— https://www.scientificamerican.com/article/our-improbable-ex...

Sure, but I think that's a form of arguing about semantics.

Let's say I argue that our universe is fine-tuned because the constants of the universe were decided by dice roll and that there are a trillion other universes with no chance of life.

What about the "substrate" within which these trillion universes formed? Wasn't it fine-tuned enough to give rise to at least one universe (ours) with life, just as our universe was fine-tuned enough to give rise to our planet?

Now I could argue that actually there are a trillion such "universe substrates" and ours is the one that's fine-tuned. However, it's clear that eventually, everything must converge to a single base layer of existence that just so happens to be "fine-tuned" enough for everything above it to produce at least one instance of life. But this is trivial.