Also, opening car doors isn't as simple as repeating a signal you captured(in general)
That said, capturing the car's question when you press the button on the door, amplifying it in the direction of the nearby fob, and then capturing and amplifying the fob's response would work for some systems.
There are a lot of reports (I’m from Germany) from car brands selling cars in 2022 which can be opened easily by repeating/relaying the keyfob signal. Newer systems which also check the signal delay mitigate this. [1] the German ADAC (German Automobile Club) did a test with 500 cars. I was happy to learn that my new car is save from the simple repeat attack. [1] https://www.adac.de/rund-ums-fahrzeug/ausstattung-technik-zu...