Among the unofficial drivers, many positions overlap depending on their roles. For instance, the third driver also acts as the reserve driver, and test drivers also drive simulators, etc.
Typically, if an official driver is absent due to an accident or is temporarily banned, the priority substitute is definitely the designated third driver, followed by the reserve driver, youth training driver, etc.
For top major teams like Ferrari, Mercedes, and Red Bull, test drivers and simulator drivers scarcely have any chance of racing.
Even when there's a rare opportunity of an official driver being absent, the team would urgently promote a youth training driver to substitute, giving them a real-world exercise to evaluate the potential of these backup drivers.
Veteran drivers often resemble a "lottery ticket" with a "thank you" note on it, implying it's better to gamble on a new ticket for better fortune.
