devtoolset is called gcc-toolset in RHEL8.
The following commands worked for me:
microdnf install -y gcc-toolset-12
scl enable gcc-toolset-12 bash
gcc --version
# gcc (GCC) 12.1.1 20220628 (Red Hat 12.1.1-3)
According to that article, you can check if you have access to Red Hat Software Collections (RHSCL) by running the following command by the root user:
$ su -
# subscription-manager repos --list | egrep rhscl
If you have, enable necessary software repo and then install devtoolset:
# subscription-manager repos --enable rhel-7-server-optional-rpms
# yum install devtoolset-8
To install the full tools-set including gfortran on centos 7:
yum install centos-release-scl
yum install devtoolset-8
scl enable devtoolset-8 -- bash
enable the tools:
source /opt/rh/devtoolset-8/enable
you may wish to put the command above in .bash_profile
ref: https://unix.stackexchange.com/questions/477360/centos-7-gcc-8-installation
devtoolset-8 was only released a short while ago. The linked installation instructions may be of use. However, your question pertains to CentOS, and this does not yet appear to have been made available yet. You can see some evidence of it being build for CentOS here, but it's not been updated for the final release yet.
You could ask on the SCL mailing list for an ETA, or wait until it appears in its final form. In the meantime, you could download the RPMs from koji directly.