The quantitative ux research team at Google was created for exactly this problem: a service which became popular before the right metrics existed, meaning metrics need to be derived first, then optimized. We would observe users (irl), read their logs, then generate experiments to improve the behavior as measured by logs, and return to see if the experiment improves irl experiences. There were not many of us and we are around :)
I worked with Boris in the past and in my experience, Boris cares deeply about the customer. I'd vouch that Boris really cares about the issue people are running into.
If you mean Google website login, that step is needed because the email address is used to determine which identity provider to use. E.g. I have three different accounts that branch off from that same initial login flow.
One is my person "gmail.com" account, and the other two go through enteprise identity providers related to my employment and their G-Suite licenses. So after I put in one of these three email addresses, I get prompted for the appropriate next step. Only one of them involves giving a password to a Google server. The other two are redirects to completely separate login systems operated by my employer.
I mean I get it logically makes sense. But it still seems like a waste of time for a small percentage of use cases.
Maybe a better approach is put in your login have it automatically detect if it requires an identity provider. Gray out the password to signal to the user password is not necessary and automatically redirect.
Less clicking, don't break flow and think of a smoother solution.