SAP Technical Lead - Node.js interview questions

The entire process began with an introductory call to understand my background and both my expectations and theirs. Then the first round was scheduled. The first round was easy to moderate, and second DSA round was easy. They asked me to attend next rounds onsite at SAP whitefield office. They didn't tell me what kind of rounds it will be or how many of them will be there. They started off with situation based questions and normal scrum practices. It was an intense session, and then they had again another round with engineering manager, he again asked behavioral type of questions and how I would tackle situations at workplace. I was offered lunch in their cafeteria, the food was good, maybe not world class but not bad either it was edible for daily consumption. There was another round after lunch for cross team fitment with a lead from a completely different team, to remove biasness. The onsite rounds were stressful and took a lot of time, almost 3 to 4 hours. What really left a bad taste for me is that after 5 to 6 rounds of both online and offline assessments I suddenly stopped hearing from the recruiter, the HR said they will inform me but there was silence for a week, then two weeks went by and I stopped taking followup. After around one month I received a rejection mail. There was no reason written except that they wished me luck and would like me to consider SAP again in future. I don't understand if you want to keep such an insanely long interview process and ask candidates to take leave from work and attend offline interviews as well, at least have the courtesy to respond on time and with substantial reasons so that the candidate can improve. As a candidate I feel my time utterly wasted and unpleasant experience, not because of the rejection but because of the entire interiew pipeline that they have setup. (From an internal employee I heard that they were not really hiring, there were few layoffs and some people left voluntarily seeing the layoff, so they just took interviews to be safe in case anyone needs to be hired)