Why didn't Japan invade Guangxi from the North Sea and enter Yunnan from Myanmar?

Taking Myanmar as a springboard to invade Yunnan, China, can give the Japanese army a buffer zone, and the Japanese army can March in Myanmar to rest and reserve logistics materials to ensure the marching quality and war supply; If we invade Guangxi directly, the Japanese army will not have a buffer zone that can be firmly controlled. At the same time, a large number of troops are invested to maintain the buffer zone and ensure the supply of materials.