I will speak from my own experience of interviewing a lot of people in the last 5 years. Age has not been a factor, it's the skillset. At a senior level, the expectation is to be a bit of a generalist and have at least one skill that you are very strong at. What I don't like about the current trend of interviews is the strong focus on leetcode style interviews, most of which you will don't get to practice when you are at a staff level.