I've been told in the past that being in a tech lead manager role is a trap.
More specifically, I've been told that it's a dead-end career path and I won't be able to focus on going deep enough to make my way to staff engineer, or I won't be able to focus on learning how to manage larger and larger groups of people to eventually be a vice president or CTO.
Will Larson (whom I have the utmost respect for) echoes this sentiment:
The tech lead manager role is a bit of a dead end. Down the managerial path, the evolutionary step is towards group management. Down the technical path, the evolutionary step is towards staff engineer. Splitting your time across both functions isn`t ideal for pursuing either path, and unfortunately it`s the rare role and organization that supports ongoing growth for folks in tech lead manager roles.
However, Larson also admits:
Tech lead manager roles are not always a bad choice. If you`ve built up your experience as both team manager and technical contributor, then sure give it a whirl if it`s what checks the most career boxes for you, but I do consistently recommend against folks starting their management career in such a role.
Personally, I've found tech lead manager roles to be extremely rewarding and impactful. Even if it is a dead-end, I enjoy this dead-end so much that I don't mind sticking it out for many years. I get to both get my hands dirty on some of the most technically challenging problems my team faces, while at the same time mentoring and growing the careers of the people on my team.
That being said, this role can be extremely challening to balance at times and you have to be very confident in both your technical and managerial skills independently to be successful at it. There's a temptation when someone on your team is struggling with a task to just do it for them, but that's not (usually) the right answer. There are also times when you have to make a conscious decision to turn away from the technical work, trusting your team, and focus on managerial challenges, like hiring, performance reviews, and career growth.
Side note: my current company has several of us in this role and is a rare gem when it comes to career growth for technical lead managers.