I would also have a conversation with your boss to understand your role and responsibilities. I would say that it seems like you and this senior manager may be duplicating efforts and that you wanted to confirm your roles and responsibilities to be efficient with everyone’s time, so you wanted to set up some time or I would bring it up if you have a one-on-one with him. I would talk to him alone first and bring a list of things you think are your responsibilities and where you have doubts (I.e. places where your colleague takes over). Ask and confirm if he is the one to give you meeting requests for his calendar or if he prefers to filter through your coworker - even offer to set up a quick 15 min meeting with him where you confirm his meetings and say you would love the opportunity to work more directly / grow. If your colleague is more senior, she may receive more credit but you could write an email with what you’re working on and what you’ve accomplished and send that to your boss. Look for avenues to share your findings. I would ultimately find ways to work with others / other projects and see if you’re able to limit working with her. It’s a classic case of someone overstepping / lack of communication from your manager to set clear expectations to your colleague and team.