KARIN STROHECKER and JOE BAVIER AFRICAN countries face another debt crisis and will need more long-term help than the latest G20 debt plan offers them to ward off trouble ahead and keep much-needed investments coming in, according to policymakers, analysts and investors. Around 40% of sub-Saharan African countries were in or at risk of debt distress even before this year, while Zambia became the continent's first pandemic-era default last Friday. The United States, China and other G20 countries have offered the world's poorest countries - many of which are in Africa - relief until at least mid-2021 and sketched out…