Management is a skill set, as is engineering, as is technical writing. Rare individuals have significant overlap of high skill in these areas, most don't. I have been a tech lead several times. In those roles I developed communication skills, mentoring skills, and planning skills far more than I had as an individual contributor. I also developed different subsets of those skills.

The best leaders though are the ones that have that overlap, are great individual contributors but have gotten to the point where they focus on tough key problems and facilitate their team's contributions and growth.

You can have good leaders that are strong in communication and planning, and ok on individual contributions. It is harder for them to plan effectively though, and they'll need to lean on their high skill contributors in the team.