Look at the example of Indonesia. Initially many Indonesians bought in to "Asia for the Asiatics" and the "Co-Prosperity Sphere". It did not take long before they wised up to the fact that the Japanese were no improvement on the Dutch, and in many ways were worse. Japanese society in the Imperial period is intensely racist - look at how the Ainu, Okinawans, and Koreans were treated for starts. To the extent the Japanese can offer Africans "anti-colonial" support but be kept at arms length that will work just fine. Longer term, you might see something like OTL where the Chinese are willing to deal with (and bribe) corrupt leaders no matter what their internal policies to secure rights to raw materials and potentially military bases.