Double war declaration on Turn 33 sounds painful. Nice job recovering from that bit of unlucky diplomacy.
I think that the Work Ethic religious belief (+1% production for each follower) was a pretty good choice for this Spaceship game. I keep thinking that's not very much since it's usually about 5% in the early game, but as a lategame religious belief goes, it's quite good for the actual spaceship part construction. I think a large lategame city could hit +15% without too much trouble, and that's a lot of time saved on those Spaceports and expensive parts. I'll have to keep that in mind for my games in the future.
One thing you might want to remember: exploration! You didn't even have contact with Greece on Turn 100 in this game, and you were slow to send any units to explore the other continent. There are a lot of benefits to poking around the map in Civ6: unclaimed goody huts (the AI is terrible at grabbing them), natural wonders to find, city states to contact, additional luxuries to target for settling, etc. I got the impression that you were kind of bored in the later stages of this game and were clicking "Next Turn" a lot, and exploring the map is one of the things that can help alleviate that feeling.
It also might be helpful to emphasize more settlers too. The Augsburg and Cologne locations that Germany grabbed in your game were mostly settled by the player in the other games. You had a really sweet early conquest of Scandinavia, and allowing Germany to settle so much of the border region gave away a lot of that advantage. I think you only settled two cities during this game, is that right (?)
Is it even possible to build universities as Arabia? I thought that Madrassas were the only option for Arabia. Are you sure that you researched the Theology civic (?) That feels like a major bug if you couldn't build research labs at all.
Also as far as the space race goes: I definitely do build Encampment districts just to trigger the +15% production from Integrated Space Cells policy.
A Turn 307 finish looks like it's somewhere in the middle of the results for this game, not bad at all. Thanks for posting such a nice report!