So here's the state of play. I took Seoul because I couldn't think of any other way to get out from the situation I was in tactically. This led France to commit to Holy War against me which was useful as I hadn't used Faith at all because I've never understood the Religion system, I bought a bunch of Apostles and converted everyone's citizens and destroyed Catholicism pretty much. France gave up this war the moment I walked into their borders and one shot everybody in their way, ceding me all their money, every luxury resource they have for 30 turns and all their great works. At which point Germany thought it'd be a great idea to go to war with me and I proceeded to own them in a massive chokepoint for 5 turns before they also gave me all their money.
A better looking image than my last:
Toggle Spoiler
I'm already at Gunpowder tech (and still losing Science apparently) and I still haven't met 7 other Civs. This is an absolutely crazy game, I literally have no idea what is beyond these screenshots and a boat sailing the high seas.