There was a total of 2 technical rounds. After this, they asked me to submit my documents so that they can release the offer letter.
Since then it's been 3 months and I have had no update on my offer letter.
I regularly contacted them for 2 months for updates but HR kept strolling me that the offer letter will be released this week, then next week, and so on.
This is highly unprofessional behavior of such a reputed company.