So have you already tried thinks like reaktor? Or the u-he bazille demo or similar plugin for cable noodle feelings? I can imagine for starting out the nodegraph with arrows type like reaktor is easier to keep overview (and you're not limited to number and types of modules), while stuff like bazille has more of the feel of actual hardware with it. In the beginning it might seem like total impossible madness. But just try wiring up some standard synth types (like 2 oscs mixed through a filter with envelope, and then through amp envelope to output) with such, enjoy them for a while, and then modify them or try extensions, and you might pretty soon learn by doing what is possible with such devices.
Important for the "modular synth feel" is the ability to feedback. There are quite some modular synth kits around, and those are probably often cool to create cool complex synth patches. But the feedback is like another dark magic dimension, together with (simulated) clipping/saturation of the modules often needed to keep things in balance.
I don't view it as the ultimate freedom of expression. It is more like...a normal standard synth has its rules and modes of operation, and everyone will find his own ways to use them for his own sound. A modular setup gives a much much more complex ruleset to find your own techniques in. You need to obey the rules, and find nice spots within, sometimes more by accident and experimentation then by completely planning it like an engineer. That is not really freedom, but it is cool also.
Here are vids of synth setups with module sequencers and such...I dunno if any external sequencers were involved, it sounds as though it could well be stuff without any pc... Now this game seems another different obscure game to me, and it is more like trying to steer controlled randomness into mindblowing results, than deliberately composing stuff. This sounds cool sometimes, but is not really my preference, I just write it so you get a little more idea of what is happening. Mod synths don't have to be used this way, but it seems to be a deeper discipline in using them. Like it is not only about ways to wire up custom synths, but also a whole shitloads of techniques to kind of create sequences of sounds that partially work via analog wired logics. A bit like creating so called "rube goldberg machines", kind of...
Many people owning stuff seem to rather like to make tweaking sessions with experimentations and such, and record them to disk. And then use the galore of different sounds chopped in samplers as material for their works. This makes more sense to me for more deliberate and controlled content creation.