What were they up to? The same thing other scientists were up to. Performing extremely risky Gain of Function studies in the hope of creating a cure and selling it.
The idea that this was created as a weapon doesnt fit. Viruses dont make very good weapons. They mutate, are impossible to control, and their use would be an attack on the world as well as yourself. Even Japan knew this in WWII hence why the Emperor shelved their plan to use them against the US.
China loves money. There is far more money in creating cures than in creating bioweapons. There are two things the Chicoms are known for: Recklessness and greed. Whether its trying to smuggle Ebola out of Africa, smuggling SARS out of Canada, stealing god knows how many patents out of the US, or damn near breaking the internet with their hacking, China makes big moves for big gains.
The number of coincidences and the anecodatal evidence pointing toward that lab in Wuhan is overwhelming. China’s reaction, the scientists working there and their previous experience, the fact that lab has 4 previous containment failures, and COVID-19’s details make it more likely than not that China screwed up big time. We were all warned about the risks of Gain of Function studies. Google it and see the timeline for yourself and what scientists were saying. They were predicting a scenario just like this.