Is it halal for one to get a credit card in muslim countries where ur not mandated to get one? If so, is the tawarruq taken by some banks, riba? They ask u to pay this extra amount if u didnt repay ur credit card dues within 60 days

The extra amount they charge for not repaying within 60 days is riba, and entering a contract that stipulates it is not allowed even if you intend to always pay on time. Also go to an Islamic bank that is trustworthy, not just any bank in a Muslim country. I have covered tawarruq in my modern transactions series.