There are several research ideas you can explore on US-China in Africa. Here are some topics that might interest you:
Chinese Economic Engagement in Africa: This topic explores the implications of China’s economic engagement in Africa for US policy. It examines the effects of Chinese economic engagement on African countries’ voting alignment with China and the US.
China in Africa: Implications of a Deepening Relationship: This topic examines China’s strategic interests in Africa and its relationship with African countries. It also explores the implications of China’s deepening relationship with Africa for the US.
The U.S.-China Rivalry in Africa: This topic examines the rivalry between the US and China in Africa. It explores the implications of this rivalry for African countries and the US.
I found some research briefs and policy papers that might be of interest to you. RAND researchers have assessed Chinese and African goals, African perceptions of China, how China has adjusted its policies to address local reactions, whether the United States and China compete in the region, and how Washington and Beijing might actually cooperate to their mutual benefit. The China-Africa Research Initiative (CARI) at the Johns Hopkins University School of Advanced International Studies (SAIS) has released a policy brief that answers how the United States differs from China in its engagement with Africa. Another article I found suggests that greater alignment between China and African countries yields greater misalignment between African countries and the U.S.