Virtualbox installs
/usr/lib/systemd/system/multi-user.target.wants/vbox{drv,autostart}.service
links by default:

$ rpm -qf /usr/lib/systemd/system/multi-user.target.wants/vbox*
virtualbox-6.1.10-lp152.2.2.1.x86_64
virtualbox-6.1.10-lp152.2.2.1.x86_64

which effectively prevent those services from being disabled.

This is rather sub-optimal in the light of mutual exclusivity of libvirtd and
vboxdrv services.

The only way to avoid starting these services on boot is uninstalling
virtualbox (or removing those links, but that's obviously silly).