KYB for non-US entities onboarding US businesses – any specific hurdles?

Running into some friction with our existing KYB provider when onboarding US-based entities. We're a non-US company, and it seems like the due diligence for verifying the beneficial ownership and operational legitimacy of these US businesses is taking disproportionately longer, even for relatively straightforward corporate structures. Are other non-US firms seeing similar bottlenecks, or is it potentially our provider's specific workflows? Trying to understand if this is a systemic issue with cross-border KYB into the US or if we need to shop for a more efficient vendor that understands US corporate registries better. The delays are starting to impact our sales pipeline.