Start-up Lessons Learned: “Everyone has a plan until they get punched in the mouth.”

When creating dotBRAND (https://shorturl.at/adrMR), our aim was to use technology to address communication problems between designers and clients. Through interviews and voting with our target audience (83 of them), we found that the top-requested features were a questionnaire system and auto-mockup. However, upon launching, we observed a preference for the questionnaire system over auto-mockup. Additionally, the actual usage by designers differed from our initial expectations. Despite my 13 years of experience as a brand designer, users' behavior with the product was quite different from what I anticipated. Have you had any similar experiences? and, what is your take from the experience?