There is generally no need to adjust for attributable earnings when the corrective distribution is made after the due date of the tax return as is the case when now correcting a 2018 or 2019 excess contribution. There is no penalty since the distribution is nontaxable a distribution of contribution basis.
The only case where I wonder if it would be appropriate to distribute earnings is if all amounts in the individual's Roth IRAs are attributable to excess contributions. It seems inappropriate that someone could establish a Roth IRA balance only by making an entirely excess contribution and then removing only the excess contribution itself. Still, an excess contribution does not start the 5-year Roth IRA qualification clock, so if that clock never gets started any earnings eventually distributed would be taxable and potentially subject to an early-distribution penalty depending on the participant's age at the time of the distribution. In your case, though, the qualification clock has started no later than the beginning of the year in which the Roth conversion was deposited into the account and the balance in your Roth IRAs is not entirely attributable to excess contributions.
