Think about this for a second, if your process worked, why wouldn’t you have used it to validate this idea? Unless your process involves posting to reddit…

not just promoting it, but creating feedback sessions and identifying opportunities and learning from the customer

sounds like your co-founders aren’t very good. They should do as much PMF validation BEFORE you build something, then post going live they should try various marketing strategies that are free, gather feedback, build an iteration backlog etc. PMF cannot be determined in 1 week lmao.