Teams are not allowed to drive their cars on track outside of a few set moments. Thereโs pre-season testing, a few days post-season, and thatโs about it. Although a few weeks back there were extra tests for the new tires.
It takes a few years (three, I believe) for cars to become freely available to teams. At promotional events youโll see Red Bull drive a repainted 2019 car, for example.