Where do brands actually find the right talent for campaigns?

Finding creators isn’t that difficult anymore. Finding someone who is actually a good fit for the brand is the hard part. We’re looking at different options for upcoming campaigns, and I’m curious how other brands usually find talent. Do you go through agencies, contact managers directly, use talent platforms, or just search for people yourself? And what do you usually check before deciding someone is worth working with audience, engagement, previous brand work, reputation, pricing, or just overall fit? Would be interested to hear what’s worked for people who’ve actually run talent campaigns.