O.K. There must be some serious issue here. I see the same problem now with systemd-udev on CentOS 8:
# dnf provides /usr/bin/kernel-install
Updating Subscription Management repositories.
Last metadata expiration check: 0:00:14 ago on Wed 21 Jul 2021 04:59:33 PM CEST.
systemd-udev-239-45.el8.x86_64 : Rule-based device node and kernel event manager
Repo : ORG_centos8_BaseOS_x86_64
Matched from:
Filename : /usr/bin/kernel-install
systemd-udev-239-45.el8_4.1.x86_64 : Rule-based device node and kernel event manager
Repo : @System
Matched from:
Filename : /usr/bin/kernel-install
systemd-udev-239-45.el8_4.1.x86_64 : Rule-based device node and kernel event manager
Repo : ORG_centos8_BaseOS_x86_64
Matched from:
Filename : /usr/bin/kernel-install
This blocks the update to the latest CentOS 8 kernel and systemd. Rocky Linux sees the same. See Katello 4.1 and Rocky Linux 8 - not ready for prime time yet it seems
Maybe also related with the error here: CentOS 8.4 BaseOS Sync error