How to best answer this question in quarterly discussion with manager? Things are looking good on personal level. On team level also project plannings are seems to be aligned with team goal. How can I add value to this question?
As a mid-level engineer, this is a perfect opportunity for you to show senior engineer traits to your manager. In terms of how to do that, I have a question for your question:
Is your experience working on the team absolutely perfect?
I'm going to guess "No" - There is no team on Earth where absolutely nothing can be improved. I'm sure there's at least 1 thing your team does or has to work with that can be made at least a little bit smoother. Zoom out and figure out what these things are with some retrospection, and from there, you can propose solutions. This is a very common behavior I see separate the senior engineers from the mid-level engineers: The mid-level engineer is mostly focused on doing their assigned work well, while the senior engineer always has their finger on the overall pulse of the team, looking for strategies to uplift everyone, not just themselves.
As inspiration, here are some common culprits I've seen keep a team from being absolutely perfect:
Lastly, I recommend this discussion started by a mid-level engineer at Apple, which talks about how to come up with innovative, impactful ideas to bring to your team.