There's currently a backlash against LeetCode style interviews, and I think one part of this backlash is that dismissing anything that feels LeetCodey (like asking about time complexity) is considered reasonable.
Which is to say i have no confidence issues in my working knowledge of Big O. I lead a team, i've developed obsessively for 10 years now and despite my many short comings i don't think understanding trivial complexity - the why of "Why is HashMap faster than BTreeMap on lookup? When is it slower?" etc - is lacking. But, i couldn't use Big O notation to any meaningful complexity with any real confidence. My math background is nil.
In general i need to up my interview game, which i think also means i need to up my math game to have a firm understanding of Big O notation itself.. but the complexity is not the issue, for me at least.