Sort of. In pwsh on Linux, ls and cp are the same binaries you'd call from bash. The Powershell equivalents, aliased to gci and copy, are implemented in Powershell, but not part of the shell, they are modules. Some core modules ship with the shell, everything else comes from the package manager (Install-Module). There is a very small set of commands implemented directly in the shell - Import-Module, e.g.
Every command is implemented in a module, it's just that pwsh ships with several core modules.
Every command is implemented in a module, it's just that pwsh ships with several core modules.