[root@tplpgrp14 ~]# dnf remove --oldinstallonly --setopt installonly_limit=2 kern
Updating Subscription Management repositories.
Dependencies resolved.
=======================================================================================
 Package          Arch     Version               Repository                        Size
=======================================================================================
Removing:
 kernel           ppc64le  4.18.0-372.26.1.el8_6 @rhel-8-for-ppc64le-baseos-rpms    0
 kernel           ppc64le  4.18.0-425.3.1.el8    @rhel-8-for-ppc64le-baseos-rpms    0
 kernel-core      ppc64le  4.18.0-372.26.1.el8_6 @rhel-8-for-ppc64le-baseos-rpms  115 M
 kernel-core      ppc64le  4.18.0-425.3.1.el8    @rhel-8-for-ppc64le-baseos-rpms  115 M
 kernel-modules   ppc64le  4.18.0-372.26.1.el8_6 @rhel-8-for-ppc64le-baseos-rpms   19 M
 kernel-modules   ppc64le  4.18.0-425.3.1.el8    @rhel-8-for-ppc64le-baseos-rpms   19 M

Transaction Summary
=======================================================================================
Remove  6 Packages

Freed space: 267 M
Is this ok [y/N]: y
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1
  Erasing          : kernel-4.18.0-425.3.1.el8.ppc64le                      1/6
  Running scriptlet: kernel-4.18.0-425.3.1.el8.ppc64le                      1/6
  Erasing          : kernel-4.18.0-372.26.1.el8_6.ppc64le                   2/6
  Running scriptlet: kernel-4.18.0-372.26.1.el8_6.ppc64le                   2/6
  Erasing          : kernel-modules-4.18.0-372.26.1.el8_6.ppc64le           3/6
  Running scriptlet: kernel-modules-4.18.0-372.26.1.el8_6.ppc64le           3/6
  Erasing          : kernel-modules-4.18.0-425.3.1.el8.ppc64le              4/6
  Running scriptlet: kernel-modules-4.18.0-425.3.1.el8.ppc64le              4/6
  Running scriptlet: kernel-core-4.18.0-425.3.1.el8.ppc64le                 5/6
  Erasing          : kernel-core-4.18.0-425.3.1.el8.ppc64le                 5/6
  Running scriptlet: kernel-core-4.18.0-372.26.1.el8_6.ppc64le              6/6
  Erasing          : kernel-core-4.18.0-372.26.1.el8_6.ppc64le              6/6
  Running scriptlet: kernel-core-4.18.0-372.26.1.el8_6.ppc64le              6/6
  Verifying        : kernel-4.18.0-372.26.1.el8_6.ppc64le                   1/6
  Verifying        : kernel-4.18.0-425.3.1.el8.ppc64le                      2/6
  Verifying        : kernel-core-4.18.0-372.26.1.el8_6.ppc64le              3/6
  Verifying        : kernel-core-4.18.0-425.3.1.el8.ppc64le                 4/6
  Verifying        : kernel-modules-4.18.0-372.26.1.el8_6.ppc64le           5/6
  Verifying        : kernel-modules-4.18.0-425.3.1.el8.ppc64le              6/6
Installed products updated.

Removed:
  kernel-4.18.0-372.26.1.el8_6.ppc64le
  kernel-4.18.0-425.3.1.el8.ppc64le
  kernel-core-4.18.0-372.26.1.el8_6.ppc64le
  kernel-core-4.18.0-425.3.1.el8.ppc64le
  kernel-modules-4.18.0-372.26.1.el8_6.ppc64le
  kernel-modules-4.18.0-425.3.1.el8.ppc64le

Complete!
[root@tplpgrp14 ~]# rpm -qa | grep kerne
kernel-tools-libs-4.18.0-477.21.1.el8_8.ppc64le
kernel-4.18.0-477.21.1.el8_8.ppc64le
kernel-modules-4.18.0-477.21.1.el8_8.ppc64le
kernel-tools-4.18.0-477.21.1.el8_8.ppc64le
kernel-core-4.18.0-477.21.1.el8_8.ppc64le