After I left, the PE firm finished the ~failed merger, flipped the company to another buyer, and the PE firm placed the CTO at another company. I've remained friends with the CTO and we have a monthly/bi-monthly check-in. He was very supportive of my side-projects and would've helped fund anything that I said had legs, but is equally eager to work with me again if given the opportunity. The company he's working at is going through a reorg and a position he thinks I'd be a good fit for (admittedly a growth opportunity) should open up.
If that falls through and I'm not able to get a warm intro somewhere then you're absolutely right. I'd focus on applying for IC positions, but clearly communicate that I'm interested in taking on leadership ASAP.