They can't seem to ever do anything properly themselves for some reason but if China takes over then they complain about all the Chinese influence
Standard third world problem. I won't blame Africa alone on this.
Europe/America learned this lesson early on (by late 1980s) which is why they largely disengaged from Sub-Saharan Africa as soon as the cold war ended. Mobutu was chucked out. A large number of dinosaurs were sent to retire. HIPC loan write off was completed. Having throughly burnt their fingers, they packed their bags and left. In some cases, like Somalia, they were sent packing.
By 2000, the only engagement the west had with Africa was a modest amount of aid and UNHCR run refugee camps.
I mean take TAZARA itself. It was an almost free gift from China at a time when China itself was poor. They later got aid from USA too, for maintenance of this line. End result? Zero.
my understanding is that China's African engagement is for geopolitics and business (export its excess capacity, secure natural resources, and develop new markets) so how's it doing by those criteria?
On the resource front, China is doing excellent, for the moment. In one of the largest mineral resource rich country in the continent, DRC, Chinese companies owns nearly 50% of all mines. It started with the SICOMINES deal (2008) and soon many other Chinese public and private companies have followed.
The associated risk is also rising, fast.
Like, really, really fast. DRC's new president, Felix Tshisekedi picked a fight with China the moment he came to power. First target was CMOC which owns 80% of the giant Tenke-Fungurume mine. It's the world's largest cobalt reserve. Felix gave CMOC a proper shakedown, to the tune of an additional $2 billion, to be paid over the next decade.
At the same time he targeted SICOMINES. The demand on this venture is an eye watering $17 billion, and he wants the Congolese govt share in the venture to be raised from current 38% to 70%! Truly the deal of the century.
Other than DRC, China has decent presence in the oil sector in Angola, Nigeria, Sudan and South Sudan. And a new plan is now afoot in Guinea, for iron ore.
The DRC situation however, is probably becoming a gray rhino for China. Chinese mining companies have poured in ~$10 billion so far into this fragile country. They are far from recovering their investments. Kinshasa knows this and I think the shakedowns will continue.
And any chance of China shipping at least light manufacturing to Africa eventually due to its own shrinking workforce (demographic decline) -- say by 2050? Because that seems to be the hope of all the B.R.I. signatories, to not just get "one-time" infrastructure but Chinese investment, including in the form of relocated Chinese light industry.
So far, only Ethiopia has managed to make sizable progress on this front. A good number of Chinese companies have opened production units there. But then they had to start a civil war (of course). Simply put, the business environment in SSA is so poor that China will most likely focus on SSA dead last. If and when Chinese manufacturing moves overseas, it will most likely go to ASEAN, South Asia, North Africa or LATAM long before it goes to SSA. Right now India alone has captured more Chinese electronics assembly investment (Xiaomi, Oppo etc) than entire SSA and India and China aren't exactly sympatico with each other (India isn't a member of BRI).
I think China way overestimated the potential of SSA and poured in too much money in too short time. To give an idea of the scale of Chinese largesse, over the last 20 years, China has funded some 30+ hydropower projects all over the continent. Hydro dams are typically very large deal. They have funded 30+ of those.
One major debtor, Zambia, has already tanked and right now China, IMF and various private lenders are having a slapfight over who will take the fall.