I got an job offer from another company but they want me to join within 45

Tell your current company that you're willing to pay a severance to be left early Ask for the same amount in the new company and settle it off with experience and relieving letter If you ask more, you can pocket the difference but then you may have to produce proof of this amount

Notice periods are straight up bad for indian economy. You know what’s it called in foreign countries? “Slavery”

90 days is exploitation. Leave ASAP, seek what is known as notice period buyout