How to remove VirtualBox vboxdrv kernel module?

I previously was using VirtualBox on Fedora 30, but recently moved to using Boxes (review) and am quite happy with the switch. I've removed VirtualBox, but upon booting up my system, I still get a tainted kernel message:

vboxdrv: module verification failed: signature and/or required key missing - tainting kernel

I've tried:

sudo rmmod vboxpci vboxnetadp vboxnetflt vboxdrv

(the other modules were being used by vboxdrv)

This appeared to remove the module, but after a reboot, the modules were back.

Since I am no longer using VirtualBox, how can I remove this vboxdrv kernel module?

Thank you for any help!