Welcome to the MongoDB community @Justin_B!
As @chris noted, Ubuntu Focal (20.04) isn’t a supported platform for official MongoDB 4.2 packages.
Ubuntu Long Term Support (LTS) releases like Focal are generally supported starting from the next major MongoDB server release following the LTS release, which in this case would be MongoDB 4.4 (July 2020).
I’d recommend installing MongoDB 4.4, instead. For information on what has changed, please see the Release Notes for MongoDB 4.4.
Regards,
Stennie