It is not a wise decision to waste another year preparing for IIM Allahabad or Bangalore because the profiles of students in the top 10 colleges in India are very similar. It is better to have a strong profile and work one's way up to the top management roles in the industry.
It is more important to focus on your profile and career growth rather than the college's brand value. It is not worth risking another year to secure admission to a particular college, especially when there is no guarantee of success.
You can get into a top 30 college and do decently, but I know of people from non-IIM colleges who are in top management roles in investment banking and top tech companies. Your success is not solely determined by the college's brand value.
You should not waste time and energy chasing a college's brand value and it is essential to focus on building a good profile and working towards one's career goals. An example is Indra Nooyi, who came from XLRI, which emphasizes that success is not determined by the college's brand value.