Complex scripting in HA (coming from ioBroker/JavaScript)

A quick question before I go down the wrong path:

what is the proper way to create complex scripts in HA? Do I need to look into NodeRed or is there a way to do it (text based) the old fashion way?

I am new to HA, but extensively started to use ioBroker a few years ago and created a couple of scripts in ioBroker using their JavaScript method (a few hundred lines of code per script).

Looking at the surface, there are scripts in HA. But it seems this is for rather (short) simple things.

Any idea what I am looking for?