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

Tru Huynh of centos.org has built the redhat developer toolset 1.1, for centos and it contains gcc 4.7.2

So you could simply use his repo and install just gcc, instantly.

cd /etc/yum.repos.d
wget http://people.centos.org/tru/devtools-1.1/devtools-1.1.repo 
yum --enablerepo=testing-1.1-devtools-6 install devtoolset-1.1-gcc devtoolset-1.1-gcc-c++

This will install it most likely into /opt/centos/devtoolset-1.1/root/usr/bin/

Then you can tell your compile process to use the gcc 4.7 instead of 4.4 with the CC variable

export CC=/opt/centos/devtoolset-1.1/root/usr/bin/gcc  
export CPP=/opt/centos/devtoolset-1.1/root/usr/bin/cpp
export CXX=/opt/centos/devtoolset-1.1/root/usr/bin/c++

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)

Now devtools-8 is available and it's possible to use it by following commands:

yum install centos-release-scl
yum install devtoolset-8-gcc devtoolset-8-gcc-c++
scl enable devtoolset-8 -- bash

It's explained in a little more detail in this answer on StackOverflow: How to install GCC/G++ 8 on CentOS. And of course, if you need GFortran, you can install it in the same way - the package is devtoolset-8-gcc-gfortran.