Onboarding & Settlement Cycles for High-Volume Alternative Payments

Curious to hear from others managing significant daily volumes through alternative payment rails, particularly those involving less conventional methods than the major card networks. We've been evaluating a couple of new PSPs to diversify our processing, and the variance in onboarding timelines and projected settlement cycles has been quite striking. One promising option for a specific regional payment method quoted 4-6 weeks just for initial KYC/AML, then another 2 weeks before we could even begin a sandbox integration. Their settlement for that particular method was T+7, which is a bit stretched for our working capital cycle, but might be acceptable if the cost savings are substantial.

Conversely, another provider, while offering a broader range of alt-payment types, seems to have a more streamlined process, quoting 2 weeks for full live readiness including integration. Their settlement is T+2 for most methods, which is far more attractive. However, their fee structure is slightly higher. This brings me to a core question: how much weight do you give to a quicker onboarding/tighter settlement versus a more competitive fee structure when dealing with volumes that can quickly accrue significant float? Are there specific red flags you look for during the initial stages that might indicate future issues with reliability or support, beyond just the advertised numbers? I'm less concerned about the standard card processing here, more about the long-tail of regional payment methods where the landscape is less mature.