The biggest challenge you will face is what I think of during interviews as "founder damage." You're used to leading teams, not being on them. You're used to deciding what to do, not doing what is decided. A good engineering lead builds and leads teams and makes plenty of decisions, but they do it in a context of "others around me are people I need to listen to" not "I'm only listening to this person because I have to because I had to get a normal job." The best thing you can do to stave off founder damage (which is a lot like hubris, btw) is to make sure you have a co-founder and/or other team members about whom you would say without hesitation "they are so much better at X and Y than I am that I look like a child next to them." Making sure you have people like that around you is how you make sure you keep learning and keep being able to fit into society. If you happen to have read that and think "there isn't anyone I know like that" then the need for those people has already reached critical importance and finding those qualities in people you know is your most important task.