Withdrawing from an accepted job offer to take a better one

Hello.

I'm from India. I have accepted a job offer with a firm in Dubai.

I have signed the offer letter with the company and submitted my degree document for attestation from Ministry of Foreign Affairs, UAE.

Now, I have received a better offer from a different company in Dubai which I want to choose.

At this point, I have received a 'Job offer for Unlimited Term Employment Contract' which I'm being requested to sign to apply for e-visa from the first company.

Will I be able to reject the offer from this company at this point? Will I be facing a ban by rejecting the offer?

I want to know the legal consequences at this point before I take a decision.

(P.S - I'm willing to bear the cost incurred by the first company in the onboarding process/acquiring work permit)