Onboarding for larger DeFi capital with traditional financial rails

Curious to hear about others' experiences attempting to onboard significant capital into DeFi protocols using traditional financial rails, specifically around the friction points with various payment service providers (PSPs) or even banks themselves. My team's finding that while smaller transfers are straightforward enough, moving seven-figure sums often triggers disproportionate KYC/KYB hurdles, extended holding periods, and in some cases, outright rejections, even when dealing with regulated entities. The spreads on some of these 'institutional' crypto on-ramps are also surprisingly high given the volume. Is anyone consistently achieving smooth, cost-effective transfers for larger sums, perhaps through a specific type of intermediary, or is this still a fundamental bottleneck for scaling institutional DeFi participation?