There isn't one magic managerial skill to be successful. You can't just put all your cards into one dominate strength and expect to be successful when managing or leading a team. I wrote about The 5 Tools a Manager needs to have to be successful and although I didn't explicitly stack rank them, I did put "Ability to recruit excellent talent" at the top of the list.
The ability to recruit and attract top talent isn't a stand alone skill. You need other things around that strength to be truly successful, but recruiting great folks to your team dictates your margin of error. It dictates how many lives you have as a manager.
In the startup context, you always have a lot of agency. Even as an IC, you get to make a lot of decisions and participate in what is being created from the onset. But there are so many things outside of your control. So much luck and chance that also has to be accounted for.
Hiring great people helps build in margin for the unexpected changes a startup must go through as well as the errors in decision making that are inevitable. Hiring great people doesn't mean you have any more time to figure it out, but it does mean you are better equipped to figure out the best course of action and it gives you, the manager, more head space to be observing from on high, rather than in the weeds, so that you can avoid the avoidable.
That goes without saying, hiring and building that great team is constant work that requires dedication. Even when you aren't back against the wall hiring, you need to be thinking about what is next for the team and to start identifying the right folks and building relationships so when the time is right, you are in a position of choice and can move quickly.
For new managers, the tendency is to want to finish your hiring cycle and get back to the trenches in delivering on your objectives. It doesn't work that way. The second you have the mandate to build a team, it never goes away. It is always something you will spend some part of your week thinking about and acting on.
A poorly built team means your margin for error is slim; you are counting on luck and tail winds to get you through. Hiring a great team means you will be able to weather whatever storm comes your way, as a team.
And it doesn't stop there. Now you have to retain those folks.