OK, so first install mock - in this example my username is ian so you will need to change that for yours:
dnf install mock
gpasswd -a ian mock
you will now need to logout and log back in again for that to be active. Now we can start building audacity from the source rpm. First download the Audacity 3.5.1 source rpm from one of the two links:
Main page with links: audacity-3.5.1-4.fc41 | Build Info | koji
Direct download for source rpm: https://kojipkgs.fedoraproject.org//packages/audacity/3.5.1/4.fc41/src/audacity-3.5.1-4.fc41.src.rpm
that package now ends up in /home/ian/Downloads on my system. Now we can build it, as mentioned there are two stages, one to deal with dependencies, the second to build the package.
mock -r rocky+epel-8-x86_64 --installdeps audacity-3.5.1-4.fc41.src.rpm
mock -r rocky+epel-8-x86_64 audacity-3.5.1-4.fc41.src.rpm
I built in Rocky 9 but I’ve adjusted the commands to match your environment. Now if that does fail to build, you can try an older version of 3.4.2 from these links:
Main page with links: audacity-3.4.2-1.fc40 | Build Info | koji
Direct download for source rpm: https://kojipkgs.fedoraproject.org//packages/audacity/3.4.2/1.fc40/src/audacity-3.4.2-1.fc40.src.rpm
maybe 3.5.1 will build for Rocky 8, so worth a try. After it’s finished building, you will have an RPM, so now I did this:
cp /var/lib/mock/rocky+epel-9-x86_64/result/audacity-3.5.1-4.el9.x86_64.rpm /home/ian/Downloads
yours will be different because it will reference rocky+epel-8-x86_64 directory, and the audacity rpm will most likely be audacity-3.5.1-4.el9.x86_64.rpm so:
cp /var/lib/mock/rocky+epel-8-x86_64/result/audacity-3.5.1-4.el8.x86_64.rpm /home/ian/Downloads
and then after that you can install it:
dnf install -y /home/ian/Downloads/audacity-3.5.1-4.el8.x86_64.rpm
and then after that when you run Audacity it should look like my screenshots 
