It would appear that there is a process to withdraw a 2020 contribution before filing by April 15 2021.
(there is also a process for after April 15, within 6 months, by doing an amended return citing a "section 301.9100-2"
See
https://www.irs.gov/publications/p59...link1000230703
(this link is for 2019 version as the 2020 version has not been released yet ! )
Suggest you call your IRA custodian, and see if they understand the process.