Onboarding Friction for High-Volume PSPs: Any Strategies?

We're scaling our fintech operation, primarily focusing on cross-border payments for SMBs, and increasingly finding that the onboarding processes with various payment service providers are becoming a significant bottleneck. It's not just the initial KYB/KYC, but the time taken for account provisioning, API key generation, and the inevitable back-and-forth on documentation, especially when dealing with different regulatory landscapes. We've tried standardizing our internal documentation, but it seems each PSP has its own unique set of requirements and preferred formats, leading to significant delays and resource drain. For those operating at a similar scale or even larger, have you developed any effective strategies or best practices to mitigate this friction? Are there specific types of PSPs or integration methods that tend to be more streamlined for high-volume, multi-jurisdictional setups? We're evaluating some embedded finance solutions but are wary of simply shifting the complexity.