"But if the earnings are income, doesn't that affect my MAGI again?"
Yes, that's an unfortunate consequence of being in the Roth IRA contribution phase-out range. You need to do an iterative calculation to determine the actual amount that needs to be distributed. In your case, the amount of the excess is rather small, so it won't take too many iterations to come up with the actual amount that needs to be returned.
Alternatively, you could leave the excess in for 2019, pay the 6%, $7 penalty, then resolve the excess after October 15, 2020 but before the end of 2020 by making a regular distribution of exactly $120 or by applying the $120 as part of your 2020 Roth IRA contribution if you are eligible to do so. That allows you to leave the earnings in and not have to deal with any iterative calculation.
