Sure, you can be a good manager and write great code at the same time. But not on the same project or company. Maybe your pet project outside of work or an open source project.
To be clear, I'm making a distinction between a great tech lead vs. a great manager. Both those roles are often confused with each other.
A tech lead will lead the project to launch by managing resources, unblocking team members, making tough decisions, writing productive code, etc.
A manager will ensure smooth operation of their team by making sure their reports are motivated, encouraged, challenged, etc. They will actively seek to recruit new team members, solve resource issues, have tough talks with underperforming reports, navigate politics and negotiate with other teams, etc.
You cannot simultaneously do both. They require very different skill sets to be good and even higher skill to be great. If you are looking to keep coding and do some of the leadership work, then being a tech lead is better for you.
