You’ll feel right at home in the command line. Install Homebrew or MacPorts. These are command line package managers. Many if not most of the software tools you are used to on Linux likely have Mac ports as well and you can find them either online or via one of those package managers.

If you are going to download software from Apple’s Apple Store, you will need to make an account. You can install software directly from the internet without needing an account. You might need to tweak some “security settings” in System Preferences to run software not from the App Store.

Unfortunately Xcode is something you need an Apple account to install. However, the Xcode “command line tools”, which includes a lot of common tools like gcc, I believe you can install by running “xcode-select --install” from the command line even without an account. There might also be other ways to get those tools installed manually / not through Apple.