@thewordgirl Firstly, I recommend that you find someone from your own network. Fiverr and Upwork are NOT the places to find a CTO. CTOs can't be found on freelance websites.
The developers who are on freelancing websites earn much more than they are going to earn when they are recruited by you. Also, building a startup is a very different ballgame; you never give up, you have to stick to the project no matter what technical challenges you're going to face.
When I was 20 years old, I was offered the role of cofounder & CTO by an IITian grad(one of the most reputed colleges in India) for a B2B SaaS product. However, I immediately refused because I didn't know the founder in person. We talked on Google Meet a few times, but I was not very familiar with the founder. Regardless of whether I had more technical knowledge than anyone else, experience truly counts. That's why there is a difference between a Founding Engineer and a CTO. I felt I was not ready yet.
The network effect is the only factor that is going to give you someone who is genuine, wants to build a successful startup, has the ability to lead, and has a lot of technical depth.