Not directly answering the question, but I just wanted to say that it's a healthy thing to encourage 1-on-1s between people in all sorts of different relationships, not just manager-report.

1-on-1s with your manager are critical because (in many cases) your manager has a big say in your career. But your manager isn't necessarily the best person to have as a mentor. Even if it's not a common occurrence at your company, I'd wager that if you approached the person you thought you could most learn from and asked if they wouldn't mind mentoring you via 1-on-1s, most people would be honored and happy to serve that role.