they are professionals. the LK in LK-99 stands for their names- Lee and Kwon, and the initial year of discovery, 1999. Lee's doctorate dissertation was about a theoretical superconductive compound that no one believed could exist. Kim was a fellow researcher recruited by Lee's mentor to help find a specific superconductive material he (the boss, Choi) was trying to create. Kim was the mechanical genius in the lab while Lee was his theoretical counterpart. they first saw this compound in the late 90s for a brief moment. they saw what they believed to be superconductive properties. they spend the next two decades plus trying to recreate the compound. during that time their chief tasks lay elsewhere but they spent time outside of work on this project. eventually in 2017 when their mentor died they gave up all other projects and assembled a lab to pursue this project full time.
they enlisted the help of another professor at korea university, kwon, who already had a lot of the necessary equipment. he also helped them raise funding. long story short, in 2018 they found whatever they thought they saw in the late 90s. they needed time to analyze what they saw. then they needed to go through the process of peer review and publication. but covid happened and the process of analysis and review was absurdly slow. fast forward a couple years and lee, kim, and kwon were working in isolation due to covid protocol. kim was working with a stateside scientist (another korean i forget the name) to independently the superconductive natures of the compound and they were achieving desired results about 1 out of 10 times. that spooked kwon, who knew that only 3 people could get the nobel prize for any single entry. he was scared of being marginalized so he rushed his non-peer reviewed publication to arXiv, which over the course of covid was established as a github of sorts for the scientific community since journalistic publication, peer review, etc came grinding to a halt.