2. Setting Up Repository
How to Install ELRepo for Enterprise Linux Based OSesInstructions on Enabling ELRepo
Then to Install Kernel 5.8 for CentOS 8
su -c "yum --enablerepo=elrepo-kernel install kernel-ml"
Especially relevant: if there is a need to have the Kernel Headers installed, you should use the Current Distributed Kernel-Headers package as that is Related to the Current Version of Glibc.
And if see a Message like “your kernel headers for kernel xxx cannot be found …”, you most likely need the kernel-ml-devel package, Not the kernel-ml-headers Package.