When George first meets the team, they are briefing Wes on the development of a vaccine for the emerging pandemic which they rewound time to stop. However, when they introduce themselves they all have a law enforcement, military, or espionage background, hardly an ideal group to develop or deploy a vaccine.
The project which George is planning, a program to help predict emerging threats, is really not suited to an app, but makes more sense for a business or government.
Archie says that they only rewind time in order to save the world, but an atomic bombing of Paris, while massively horrific, would not constitute the "end of the world".
Archie implies that the Lazarus Project is responsible for the rapid development of the Covid 19 vaccine. However, the project's "backstop" date is July 1st, and the initial Covid vaccines were developed by March of 2020. The remaining time until their public unveiling in November was used for human trials to make sure they were safe and effective.