Q. "So if I decide to ignore it, will I have the same problem when I file 2020 taxes since I would need to show what happened to the car? "
A. No, just delete it.
Q. "If I decide to go through with it, what is the gain or loss basis? For example, if I bought the car for $20,000 and it valued at $14,000."
A. Your cost basis is $20,000 minus the depreciation portion of the mileage allowance (26 cents in 2019). That's why there's seldom any capital gain or depreciation recapture, when a vehicle is sold or disposed.
