The short answer
Invert the order. Instead of configure everything then use the product, give people a working demo environment with realistic sample data so they see the outcome first, and let them replace the sample data with their own once they want to. If the setup involves someone else, an admin or an engineer, treat that handoff as the real bottleneck and design around it: a shareable setup link, a status page, a nudge to the right person. Also be honest about which parts of setup are for the customer and which are for you, because most onboarding forms collect fields your team wants rather than fields the user needs. For genuinely heavy products, the answer is often to price and staff onboarding as part of the product rather than pretending it can be self-serve.