Hope this can help. THe best of luck to you :)
Take OpenAI as an extreme example. The UI was basically a POS and it was difficult to even navigate to ChatGPT when they launched. It was just such an awesome service that people paid for it and used it. Focus on the business you are creating not the software you are using to deliver the service. Honing a UI can come later.
In a world where code is a disposable commodity, it is the business that matters. What specific problem/service are you trying to provide?
Some things I have paid for: -ChatGPT -Amazon Prime -Genscape/Wood Mckenzie crude oil tracking -Netflix -Bloomberg Terminal -LSEG -Disney+ -a finance substack -Cell phone data
Many of these have atrocious interfaces. I pay because they solve real problems in the real world for me.
A common issue among (particularly young entrepreneurs) is thinking, "I want to get into SAAS.", then focusing on some website or UI first.
In a modern world, that is the last thing that matters. What matters is solving a real problem for people.
What is the business you want to create? What is the market? What is the problem you are solving for them. What are you providing people to save them time or money or entertainment etc? That is what matters.