What should I do with my time, losing the sense of purpose

I'm a final year Btech UG (21 F). Received an okayish on campus offer for analyst role. Not receiving responses for off campus applications. I built a good grasp on python, sql, quant, LRDI, basic ML for the prep. Couldn't get into DSA.

I require some guidance on how to spend the 4 months before joining.

I've been binging series, reading some fiction, scrolling on different apps, but nothing productive. Went on a trip, but got sick there. I have joined a local gym, but it takes up only 1hr of my time. Don't want to do unpaid internships.

I don't have any idea on how to prepare myself for the job either. Should I prepare for senior level interviews? If so, what and from where?

Should I prepare for the CAT now or give it a couple years later? I don't know if the MBA still holds relevance anymore.

All advice is appreciated.