So it’s GT6U? Well I didn’t know.
I tried some modpacks before, but I found it overwhelming to learn with so many mods together, many of which I never played nor investigated before. And I don’t dare editing configs or adding/removing mods, since I feel like it’s many sophisticated mechanisms (which I don’t have the brain to understand) organized together into some monolithic and delicate stuff.
Thus I prefer to explore and install mods myself, sometimes alongside playing (retrogen is such a good thing!), according to what I find to be needed.