How to install devtoolset-11-gcc-c++ \

Hello, Im having a hard time installing devtoolset-11-gcc-c++
on Rocky Linux 9. Can someone help me install it? thanks

Why?

The default GCC on Rocky 9 is version 11. There is no need for “developer toolset” for that.
Easiest way to install the default is: dnf group install development

If you would need a more recent GCC, then there are:
gcc-toolset-12
gcc-toolset-13
gcc-toolset-14
See dnf list \*gcc\*