Infrastructure. Full stop.
In smaller companies the head guys are used to having their fingers in everything and making most decisions. They don't adapt as a company grows. They continue to micro manage, they continue cultural things such as inclusive conversations etc. So you become heavily matrixed, lots of people in meetings, consensus decision making. Bogs companies down.
Your job as an exec in a bigger company is to set a vision/strategy, tell people what's expected of them and empower them to make it happen...and then rate them on their performance against expectations.
Dedicate your time to looking deep into the future, building decision support systems, creating performance standards and reward systems and maintaining a lean and efficient org chart. Spend most of your time there. If you don't the org collapses under its own weight. Culture building is a part of this too.
The process to engage in and understand the day to day must be simple and take up very little of your time. Here's a test: if you want to know something that's happening in your company currently, do you turn to your laptop or smartphone to engage a system or are you engaging a person? In other words, can you google it? If you are engaging a person more than 1 out of 5 times you're inefficient and will cause meetings and report generation (by humans) to explode. You're cooked. (and PS your inspired team will start hating their job).