Well, there's really two ways it works at my company. The other way it works is managers making backroom deals and then it's just some conversation with the tech lead that counts as the interview for HR's sake. So sort of similar to what you described.
And totally agree with the absurdity of the questions we ask in tech interviews. At least for my current employer, we use simplified versions of real problems we faced in the past, and place more emphasis on how they communicate, rather than just throwing some leetcode medium/hard problems, and let candidates self select based on how much prep work they put in.