What is the relationship between Dongyi and Jiuli?

It doesn't matter. Dongyi is the name of Qing, Yan and Xu, that is, the non-Han people in the lower reaches of the Yellow River, and Jiuli is the name of the non-Han people in the lower reaches of the Yangtze River (and further south). In the past, China was surrounded by barbarians, the barbarians in the east were Dongyi, and the barbarians in the south were Jiuli.

Not all Shandong people are Dongyi. Qilu and China are both non-barbarian countries. Jiang Taigong was enfeoffed and competed with Dongyi for territory. But in fact, the Dongyi civilization is not inferior to the Huaxia civilization or the modern Chinese civilization in the pre-Qin period, but strictly speaking, it is a "greater China" civilization that has infiltrated the national civilizations such as Dongyi and Jiuli.