A founder came to you with just an idea and you went on to build it? You should have been a cofounder from the beginning.
I just took the project as a consulting project so I didn't expect much. And a founder was only looking for DEV!
It sounds like the CTO should have been hired as a tech trainer for the existing CTO == you.
I see it again and again in early enterprise. When a dreamholder feels underpowered at the real task of delivering product, thdy build layers of admin to lower the product delivery team, burn through CapEx and OpEx and label that 'growth' and eventually the % promise is worthless.
Production teams beware of founders who just need a dev and not a team of partners. Ego > Ability & Manipulation skill instead of leadership capability.