I thought i was pretty well versed on how the republic works, but someone brought something to my attention. Why even have states without an electoral college? Why even have a senate? and then, how do you ratify amendments without those two bodies?

The electoral college isn't just a way for smaller states to have representation. It is integral to the federalist system. There is no way you have the same republic without it. States become administrative districts, the senate becomes obsolete, you essentially have a house of representatives and an executive, all of which function based on popular vote. There is no structure at that point. It is a pure democracy, no republic would exist any longer.