I've experienced the transition from being an engineer to a manager, and then from a manager to director, from director to VP, and now CEO.
I can tell you by far the most material impact on my ability to take on more responsibility has been having a great manager (not just a mentor). A manager knows what work you're being asked to do, sees you try to do that work, and can give you feedback on the work that you're doing. A mentor just does not have that context.
It's so important that one of the questions I ask when interviewing people (at any level) is tell me about a great manager you've had. And a shockingly large number of people (even directors or VPs with impressive resumes) will say "I never had one, but I wish I did."
This is a longer-term advice, but I would make it a career goal if you want to grow to try to find a really great manager.