KYC Automation vs. Manual Review for SME Onboarding

We've been grappling with the balance between full automation and manual oversight for our KYC/KYB process, particularly with small to medium-sized enterprise (SME) clients in the fintech space. While our automated solutions handle a significant volume efficiently, the edge cases involving complex ownership structures or multi-jurisdictional operations still trigger a lot of manual review. This creates bottlenecks and raises questions about the cost-effectiveness of our current hybrid approach. I'm curious to hear from others who've scaled their SME onboarding: At what point did you find the ROI on further investing in AI/ML for these edge cases started to diminish, versus simply maintaining a robust, well-trained manual review team? Are there specific types of corporate structures or red flags that you've found are simply too nuanced for current gen automation to reliably flag without significant false positives or negatives?