MU 2036 by China Eastern Airlines fly from Dhaka Airport to Kunming. It seems there is no flight from Kunming to Liuzhou. The fatest train is K182 from 17:54 at Kunming and arrive in Liuzhou nearly 15 hours later. Or you can fly to Nanning first and then get to Nanning Langdong Bus Station to take the bus to Liuzhou. It takes about 50 minutes from nanning Airport to the bus station and three hours from Langdong to Liuzhou. I think the night train is a good and easier choice if longer time is not a problem.