Also, France, Brazil, US, UK, Italy, Türkiye, Saudi, UAE, India, Pakistan, Qatar, Egypt, South Africa, and Russia all have stakes and investments all over Africa that outcompete Chinese investment (depending on the country).
So on a continental level is China the biggest investor?
That said, "European investors remain, by far, the largest holders of FDI stock in Africa, led by the United Kingdom ($60 billion), France ($54 billion) and the Netherlands ($54 billion)" [0].
China's OBOR tends to be infamous largely for it's infeasibility. It's the IDC equivalent of a subprime loan, as most OBOR projects in Africa tended to be those that larger FDI contributors decided to pass on.
There is a regional segmentation aspect as well. Africa is large and some regions saw outsized Chinese investment (DRC for example), but in other regions there was much more competition. For example, most FDI in the Horn of Africa (Djibouti, Eritrea, and Somalia) and North Africa came from Europe, Türkiye, and the Gulf States.
In the former British colonies in East Africa (Kenya, Tanzania, Uganda, South Sudan), Indian Ocean (Seychelles, Mauritius), and Mozambique Chinese companies were directly competing with long established Indian and Pakistani conglomerates due to the centuries old existing Asian business community in the region.
In Southern Africa China would be competing with South Africa along with smaller players like India.
I can't speak for the rest of Africa, but I've seen China having a significant impact in West Africa and the DRC.
[0] - https://unctad.org/press-material/investment-flows-africa-dr...
Highly unlikely because the world of Infrastructure Development Financing is a highly competitive one.
The American, EU, Australian, and Japanese funds get the best projects, and the remaining ones (mostly in LDCs) go to upstarts in the space like China, Korea, Taiwan, Israel, Türkiye, Saudi, UAE, India, Qatar, Thailand, Indonesia, Egypt, Russia, Mexico, and Brazil.
Most OBOR projects failed because they were projects most other lenders like the ADB or WB wouldn't touch because of their risk profile.
There's a reason why when SK was in a similar position as China today in the 90s and 2000s, they went all in on investing in China and ASEAN. Hell, the Japanese did the same thing in South Korea in the 70s and 80s.
China doesn't really have a similar option. Most of the stable ASEAN members (Malaysia, Thailand, Vietnam, Indonesia, Philippines) prefer Japanese, Korean, or Singaporean FDI, and the only other China-esque market for China to potentially invest in is India, which has made operating a Chinese owned subsidiary a living hell while rolling a red carpet to Japanese, French, Singaporean, Gulf (excluding Qatar), American, and Israeli investors.