But to what benefit? If the virus has a short incubation period, it is worthless as a weapon because it will "burn out," in other words kill its victims before it can spread too much. If it has a long incubation period, it will kill everyone including those deploying it unless they have a cure or vaccine ready. Even then these types of viruses can mutate rendering pre-prepared cures and vaccines useless.
The whole exercise is pointless even from a military point of view.
Never fear. I'm sure they are working feverishly to iron out those bugs.
The Chinese have been attempting to create a virus that would preferentially exterminate people of non-Han Chinese genetics. They even wrote about this in their military journals a few years ago, detailing a scenario where China could repopulate the North American continent after a plague had removed all of the previous residents.
We have our lunatic fringe. So do the Chinese. Both groups include persuasive (and very psychopathic) individuals who manage to get access to government funding from time to time.
COVID-19 was their first prototype. It did not work as it was supposed to work. And then there was an "Oops" in the Wuhan lab.
"Disease X" will have a similar progression. Hopefully, we will be lucky (again) and it will not work. If it does work, it will only be a problem for the 2% of the human race that survives the plague.
Spoiler: That won't include the Chinese people or the members of the WEF councils. Their very names will have been forgotten in the aftermath of such events.
Plans usually do not work out quite as expected.
“But to what benefit?”
To see if they can do it, or to make it to “find a cure” before it occurs naturally. Something I call “stupid virology tricks”.