What to expect
If things go well after you finish the entire interview loop, you may get feedback in as little as 1 week. This could be longer if they have a lot of candidates to interview. If you did not perform well, the loop may end prematurely, and you may get an automated message thanking you but they are moving forward with other candidates. Do not be discouraged. I estimate it takes at least 50 applications to get an offer for a job you may really want, taking 5-10 interviews. Very few people apply for one role and get an interview and an offer. There is a lot of competition for high-paying technical jobs, so be patient and try to stack the deck in your favor as much as you can.
Normally, after every round, you have the opportunity to ask questions, so feel free to ask about the next stage and gather some early intelligence. If you need more time to prepare, don't rush your interview...