Mashable SE Asia's claim that the continent of Africa will split as a result of a new ocean being formed have actually been claimed by more reliable news publications in the last three years (Mashable SE Asia). Notably, NBC news covered this claim in their 2020 article titled "The African continent is very slowly peeling apart. Scientists say a new ocean is being born."
In this article, NBC journalist Denise Chow discusses how a crack in the Earth was discovered in Ethiopia in 2005. Alike to the article you supplied, the NBC article explained that this 35-mile crack was a split that was "equivalent to several hundred years of tectonic plate movement in just a few days." (NBC) As this was such a fast occurrence, geologists such as Cynthia Ebinger are still searching for direct answers and possible preventative measures. Ebinger's current theory on this event is "built-up pressure from rising magma [that] could be triggering the explosive events seen in the Afar region." In the wake of this split, more splitting will potentially reshape the continent of Africa.
Tectonic plates, explained by National Geographic as the "theory that explains how major landforms are created as a result of Earth’s subterranean movements" are a primary agent of this split (National Geographic). Three tectonic plates, the Arabian Plate, African Nubian, and African Somali, are currently all moving at different speeds and different directions away from each other. These movements are small, about 0.2 to 1 inch per year, but these shifts can make great differences in the surface of the Earth.
Eventually, continental rifts become oceanic rifts. Christopher Moore, Ph.D. doctoral student at the University of Leeds interviewed by NBC, explained that this rifting process is already underway. On these splits in the Earth, oceanic crust forms preemptively before becoming an oceanic rift. According to Moore, oceanic crust has already been reported on this specific rift, as it can be measured to be a different composition and density from other crusts that may exist on similar rifts. With this discovery of the already forming oceanic crust, experts do believe that the shifting of these plates underneath the continent of Africa will eventually result in a new ocean forming in its wake.
With a claim as exceptional as this, it is understandable to question your sources - but in this case, your source was correct in its claim, backed up by other notable publications. IFL Science, another website who covered the claim, confirms that this change should not occur completely for another 5 to 10 million years (IFL Science). In this case, Africa's new landscape and ocean will not happen during our lifetimes.
Mashable EA Asia source (yours): https://sea.mashable.com/science/22731/an-entirely-new-ocean-is-forming-that-will-split-africa-in-two-scientists-say
NBC source: https://www.nbcnews.com/science/environment/african-continent-very-slowly-peeling-apart-scientists-say-new-ocean-n1234128
National Geographic Source: https://education.nationalgeographic.org/resource/plate-tectonics/
IFL Science Source: https://www.iflscience.com/africa-is-splitting-into-two-continents-and-may-open-a-vast-new-ocean-67848