I am so confused.

I am interviewing for a new position. I made it through a phone interview, where we discussed the position and the skills required, and it went well. I was invited to a second round asynchronous, survey-style interview. It was extremely long and took 3 hours, resulting in 9 pages of input... but ok, makes sense, they wanted to make sure I knew what I was talking about. I passed that round, and now I'm on to round 3, which is a 3rd party quiz style skills test. I generally don't like these because I find that the questions are too rigid and specifically in terms of tech, are out of date. But I went in and did the test... to make a universal comparison, it's like they asked me in round 1 if I knew how to drive an automatic vehicle on a sunny day, then came out with a manual monster truck rally in the mud. The questions were FAR more advanced than the role and skills we discussed. I have no doubt I did poorly. A few of the sections I didn't even finish because the timer ran out. I feel disheartened and embarrassed. Before going into this assessment, I felt like I was an extremely good fit [based on my conversation with their HR person and the job description]. I would not have agreed to continue the interview process, as it is a waste of both my time and theirs. I did sent a three sentence email to my HR contact letting them know I had finished the assessment but that I had concerns. I thanked her and repeated my interest in the role as it had been described. I'm just feeling so off balance. After so much time invested, I might lose this opportunity because of an automated assessment that doesn't match the skills in the job posting. Is this how things are done at larger companies? I've traditionally worked for much smaller mom&pop employers, and this is the first time I've had to do a 3rd party assessment for a role.