How to define a command like `\node` of `tikz` package

Question

With tikz, we can write

\documentclass{article}
\usepackage{tikz}
\tikzstyle{mystyle} = [rectangle, text centered]
\begin{document}
    \begin{tikzpicture}
        \node [mystyle] at (0, 0) (mylabel) {mytext};
    \end{tikzpicture}
\end{document}

How to define a command that can work like \node?

As a subquestion of that, what are the terminologies to talk about commands like \node in the aspect of language? A parallel example in Python is that when we define a function, we have positional arguments, keyword arguments, decorators .etc as follows:

@decorator
def function(pos_only_arg1, pos_only_arg2, /, arg1, arg2, *, kw_only_arg1, kw_only_arg2):
    ...

Is there similarly straight forward illustration for defining commands in latex? In the case of \node, I am particularly interested in the syntax at (0, 0) and [mystyle], which it seems impossible to implement with just \newcommand.