If you have a thin file, then it’s probably more a question of what you can get, rather than getting the best one.
Try an eligibility checker.
If you manage to get one, you use it and clear it in full each month when you get the statement. That way you pay no interest and APRs aren’t a factor.
Using one well will then build a credit history so you can get a better one with things such as no foreign exchange fees. But anything will do as a starter and better late than never.