Should I resign from my current job?

Hello, I’m a MERN full-stack developer with 3.5 years of experience. My current salary is only 5 LPA, which I believe is underpaid. I work at a Lala company and am considering switching to a better one. I’m curious if I should resign without a job offer in hand. It’s almost impossible to apply for jobs while working here because if there’s an interview scheduled I have to make up excuses to take leaves so I can give interviews. The managers are rude and only approve leaves for legitimate reasons. Please guide me. Thanks.