HARTING Technology Group Engineer interview questions

Too many rounds. 1st initial reached out by HR then 2nd 1 hr round with HR same person. 3rd 1 hour round with hiring team of 4 from across the globe so meeting was set up early morning to accommodate all. Then final round with 4 interviews 1 hour long each and tour of the facility total 5.5 hours for this round. At the end of all these interviews, they ghosted me for 2 weeks and upon reaching they said they went with some other candidate. I don't understand when they really liked me and went ahead with all the rounds then why would you waste time and energy of candidate by taking 10 hrs and kept moving forward. The interviewer should make their mind in 1st 2 interviews.