Same for me. ROS in particular only supports Ubuntu officially; although I know people can run it on Arch, it’s much more hacky and you have to build every package from source.
There are packages for ROS in the aur. And there are wrappers for the commands needed to install packages from AUR. To install ros on my system I just need to execute
pacaur -S ros-noetic-desktop-full In this case it will indeed compile the package with cmake. But there are also many binary packages on the aur. The user experience is not like Gentoo. I have never had problems finding a package with Arch.