The IRS is not offsetting 2020 federal refunds for student loans.
May I ask where you received your information? I am only wondering because I have just started receiving notices from my loan servicer demanding payments and threatening garnishment again.
Collection activities are currently paused through Sept. 30, 2021, which could protect your 2020 refunds as well. The Department of Education has said that borrowers with loans in default will be given the opportunity to enter a payment plan — which would prevent tax refund garnishment — before collection activities restart.
For confirmation you can contact the Bureau of the Fiscal Service, (BFS) the department responsible for the Treasury Offset Program (TOP) and collections using taxpayer refunds due to debts which include student loan delinquencies.