A problem with European peace makers is that they can be seen as invaders by both sides.
UN intervention OTOH can mean that African nations can provided peace keepers with the developed nations footing the bill. For the UN to intervene there must be recognised genocide. In Rwanda there was a political will by the US, amongst others, to deny that there was genocide thus stopping UN intervention.
I don't know Africa to any great extent but I can read a map. The DRC would comfortably cover the whole of the western European peninsular, ie south west of the Polish border and including all the blue bits. Just how many troops and how much air support would be need just to sustain the troops?
From the CIA World Facts Book there were 66 million peoples with a median age of 16. There is only 6 cu m of water per head per year.
I know we could say it is impossible so we should not waste resources and lives or that whatever we can do would only be a sticking plaster.
Let us assume that European and UN troops are used. How many would be needed, how would you depoly them?