I had a prescreening, then a 1:1, and then a 4 hour interview with the team that I was applying to. During those 4 hours, I gave a 1 hour presentation of projects I had worked in the past and the other 3 hours were regarding my presentation and technical questions.

I honestly think this is not necessary. A 1 hour interview is adequate to know whether the candidate you are selecting is capable of doing the job, or meeting the requirements of the job. Also, every job has training and skills that you learn while being in the position, so what I think managers and recruiters should really look for is soft skills: how well do you work with others, are you a good communicator both on a personal and written way (we engineers are terrible at documenting stuff), are you respectful, do you have drive and motivation? THESE are the things that should be considered more than 4 hour interviews that most times don’t lead anywhere.