How powerful is Hamura compared to his brother?

What the title says.

Peak for both?

Peak for both.

We don't know how powerful Hamura was at his peak, but peak Hagoromo had the Ten Tails' chakra, and both Six Paths seals. Hagoromo was definitely the more powerful of the two based on what we know, and I think the gap was fairly big.

So maybe akin to the difference between Hashirama & Tobirama.

Bump; according to the Last novelization, Hamura's tenseigan could have restored the earth in the event that it was destroyed by the moon. (That was Toneri's plan, to eradicate the shinobi world by crashing the moon into the earth, then restoring it and restarting)

This favorably inclines me towards Hamura being equal or nearly equal to Hagoromo; that said, a Hashirama/Tobirama relationship between the two is implied in the anime. That would mean that Hagoromo is planet-level, though.