If UI is a blocker to launch, you should probably just solve that issue for the short term. There are many wonderful designers in the world. I recommend going t

If UI is a blocker to launch, you should probably just solve that issue for the short term. There are many wonderful designers in the world. I recommend going towards the smaller shops that will be iterative with you - in my experience the bigger ones just want to take a list of requirements and design 10 screens while the smaller shops are willing to work with you to create a compelling design (and actually understand your use case!) for just a handful (which you can then apply the principles to the rest of your app). In my case (startup currently consisting of just myself), I have a lovely designer who I contract with and I’m able to do just enough UI work to get by between projects with her. I highly recommend the “Refactoring UI” book for giving developers the skills to do the bare minimum of UI design (it’s relatively short and gives actionable principles). there’s no substitute for having someone who really (tries to) sit in the users shoes and figure out what a good (minimal!) experience should be.