@wittyomnivore42 I can help, I've had to explain the Abandoned Car issue so, so many times now...
Abandoned Cars were essentially a limited time event running from late 2017 to mid-2019, where each week or so a unique car (often a "hero" car from a previous game, boss car, or even an exclusive FVPD Crown Victoria) would spawn in a pre-set location within the offline single player career. You'd drive to the car, collect it, then evade the FVPD whilst driving the car you collected back to Airfield 73. After that, it was yours to keep, though you couldn't visually customise some of them. However, there's no rotation cycle anymore as the developers are no longer updating Payback.
So in short, Abandoned Cars are now inaccessible as they were a series of time-limited special events. Neither Xbox Live or EA Access will be able to unlock them for you, as they simply aren't in the game anymore. As for other content you mentioned, it's most likely DLC that you'll have to pay for separately, such as the Speedcross events or additional car packs.
Sorry to disappoint you, hope that helps?
