Speaking from 2e (~120 years before BG3), giants mostly lived together in small groups of a few families at most, so they didn't have much of a lobby beyond their size and strength. Hill giants are/were evil savage brutes would have probably accepted the violence they can enact as payment to join the Absolute. Two or three hill giants would have been a great addition for the goblins in Act I and I would be surprised if the Absolute Army didn't contain at least a few hill and/or mountain giants. Since cloud giants were good-aligned, the presence of evil giants in the Army of the Absolute could serve as an IG explanation for the sudden appearance of cloud giant fingers.
