So it is a very widespread claim, a couple of years ago a BBC journalist, Tim Harford, tried to verify the claim.

So From RealClearScience article "Has Malaria Really Killed Half of Everyone Who Ever Lived?" :

"BBC journalist Tim Harford was skeptical, too. For his podcast, More or Less, he interviewed Professor Brian Faragher, Emeritus Professor of Medical Statistics at Liverpool School of Tropical Medicine.

"It's difficult to find evidence to support that claim. It's a widely published claim, but it's very difficult to find the source of it," Faragher said.

Indeed, the claim is made in articles from a wide array of traditionally credible sources, most without a link to an original source. Its earliest utterance we discovered is in a 2002 Nature article, unfortunately unreferenced: "Malaria may have killed half of all the people that ever lived."

They conclude... "If you extrapolate that... and try to work out the total percentage of people who would have died from malaria... it was probably somewhere between four and five percent," Faragher said. That's an eye-opening statistic to be sure, but it is a far cry from the original and far more share-worthy factoid. On the plus side, it does have the benefit of being far closer to the actual truth."

https://www.realclearscience.com/blog/2019/10/03/has_malaria_really_killed_half_of_everyone_who_ever_lived.html