The 2020 Form 1099-R for a return of contribution from the traditional IRA taxable on the 2019 tax return will have code P (presumably along with code 1), not code R.
Given that the contribution was $6,000, presumably your wife was under age 59½ at the time of the return of contribution, so on the 2019 tax return the earnings will not only be subject to ordinary income tax, they will also be subject to a 10% early-distribution penalty.
