This was a bizarre process and highly disrespectful to the interviewee - this was the worst interview process I've ever done simply because they had no idea what they were doing and just trying to make it as time-wasting as possible.
I spoke to 3 recruiters and only finally spoke to people I'd work with in 1 interview at the end, so both sides had no way of knowing if it would be a good fit and I wasted a ton of time. You should meet the hiring manager at the second stage to see if it's a potential fit, not stage five or however late it was. There were also probably 5-6 hours of tests that had absolutely no basis in or relevancy to the job I was interviewing for. I put that this process was "difficult," but it wasn't really - it was more "difficult" in terms of wasting a ton of time and making zero sense, but it was "difficult" because it was actually testing your knowledge of anything relevant.
The recruiters seemed very green and like they had no idea what they were doing but had huge egos. One even asked me something like "How do you handle tasks you don't enjoy?" as though that's not an inherent part of any job.
They also lied about giving you a free year of their services if you submit a review for the interview process. I didn't even want a year of their services since they're the epitome of ensh***ification, but after I submitted the review, they didn't send me anything, which is an incredibly bad look. I was only sticking with this process because it paid for relocation, which is rare, but yikes this is not worth it. I can't imagine how terrible of a workplace it is if this is how the interview process goes.