Hey Rushabh! @david2 was telling me the other day about this plugin https://www.whatruns.com/ that will show you some of the website’s stack.
AWS is used for hosting, I know they use PostgreSQL on RDS and my understanding is that apps are containerized with different containers for test/live versions (but not sure).
Theres a some of this information on the forum, mostly in posts by Emmanuel and Josh, and there is a job posting at https://bubble.io/jobs that has some of this info too.