Finally got around to playing this again. Replayed from ~t240ish. Built a lot of markets+theatres for happiness, and few banks where it made sense. In my first attempt, I sent my stack straight in instead of letting Saladin's stack come into me to not suffer war unhappiness, and was immediately at -300gpt after 2 or 3 turns. Also went back into HR since keeping Napoleon friendly doesn't matter anymore.
I got quite lucky here. Qin peace vassaled to Saladin, but freed himself the turn I was going to attack. I don't know why because Saladin has converted 2 cities from sushi and is significantly stronger than Qin
The first 2 turns were very scary, probably took an hour just to play those out lol. I think I lost 4 border cities immediately and then counterattacked with my CR tanks. Lost over 60 tanks just from these 2 turns.
Once the initial wave of units was taken care of, I sent a stack of about 80 forwards.
I could no longer build tanks so I checked around to see what happened
The rest of the war was going well so I just ignored it and kept pushing. Medina fell and I got 2 corp HQs + Hollywood, very handy.
I was just now starting to retake my border cities. I had less cities than I started the war with but Saladin wants peace now

(see those ruins south of the oil? I misclicked raze city and didn't feel like reloading lol)
Something pretty bad happened here but I don't have a pic. Saladin built up a small stack in the fog of war and slammed it into Mecca. I lost 20 tanks in 1 turn and was left with just 6 or 7 half hp tanks left. I couldn't move reinforcements in quickly because it was surrounded by culture, so I just doubled down and took all the south cities. I didn't wait for any EP discounts, just took them as fast as possible. In the end Mecca just barely held.
War unhappiness is 10-15 in every city, even with forges/markets/theatres/jails in most cities, and I really want just a few turns to reset, get some more EP stored up, and get tank numbers back up. So I push to Baghdad with everything I have. This battle was on a knife's edge, I had just barely enough tanks to consider taking it.
...and with that, I ceasefired. I don't care if he vassals to anyone else, I'm the strongest in the game. I've lost 180 tanks and have ~80 left.
Saladin is done with the tech tree, but is still 5 parts away. His capital is in Kufah and I should be able to destroy it if he launches.
Qin is building parts, but he doesn't even have composites, so I'm not worried about him right now.
Culture win is still 100+ turns away.
Vassals can still win if they launch a ship right? I think I need to just wipe Saladin.
Game looks to be in the bag