This is asking a lot from you, but in your situation, I think your goal should be to build up enough of a relationship with your manager that you feel comfortable telling them that, or realize that that's never going to happen at your current company and find a new job.
I have reports who have told me that they're happy doing what they're doing. I don't see it as a negative at all - they're employees who are quietly getting their job done and I don't have to worry about them leaving for career growth or Peter Principle-ing them into incompetence. It's important that we continue to have 1:1s though. People aren't static, they can change their mind, and I also want to make sure I keep an ear out for little things that are annoying them, and do what I can to make them go away.
I have reports who have told me that they're happy doing what they're doing. I don't see it as a negative at all - they're employees who are quietly getting their job done and I don't have to worry about them leaving for career growth or Peter Principle-ing them into incompetence. It's important that we continue to have 1:1s though. People aren't static, they can change their mind, and I also want to make sure I keep an ear out for little things that are annoying them, and do what I can to make them go away.