SaaS startup - Tech Co Partner Question

Hi everyone, In short, I am a non-technical founder planning a forthcoming SaaS project. The idea is there, the validation is secured, 2-3 dev agencies have been shortlisted and the investors are onboard. Everything seems on track right now but I can't help but ask myself: "should I really be going into this all without a tech guru by my side?" Up until now, I just assumed that the dev agency I choose to work with would fulfil this role. Such assumption has been challenged after binging weeks worth of YC combinator (top quality stuff) as they are adamant that a technical co-founder will have a massive influence on the companies trajectory. I guess what I'm trying to ask here is what I should do right now. Do I just carry on with the way things are or would finding a tech co-partner be the right way to go? If so, how would I even find someone... Any help would be greatly appreciated.