Saint-Gobain Research Engineer interview questions

I was contacted by Saint Gobain Research, Chennai by their technical recruiter for the position of Research Engineer-Sustainability. The interview spanned across 4 rounds virtually within 2 weeks. The first round was a generic one with 2 people from research and 1 from HR team. Within a day, the recruiter mailed to prepare for a technical presentation that was scheduled within 4 days. And the third round was scheduled with their one of their senior manager and the 4th round was with their senior director and senior HR, both of these scheduled within the next two days of the technical ppt round. The last 3 rounds were technical and they asked me several questions from my career experiences. Now the worst part is after that the recruiter never contacted me, and it has been a month since the 4th round. So they schedule interviews without looking at candidates' desired time or flexibility but they never get back to you after the process is done.