There is another way to get aluminium besides on the map
Yeah, it was one of those things where if you know the map, you can change how you decide to play. Knowing there's none, you play the game differently.
I found that once you get past the initial pesky GDRs roaming, it was pretty calm the rest of the way. Maybe I just got lucky in their spawns, but once I got my core like 3 cities down with encampments around, I only ran into trouble with them if I ventured off into the wilderness. A couple times I like had a builder or settler stolen, and then tried to send like a couple tank armies to get them back, but they both got killed easily. Just turtling up, expanding out slowly, they never really bothered me. One of my "smart" plays was parking an early battleship in my 2nd city, which was nice to get a ranged attack. At least, it was smart once I build my first battleship and left it out, and it was one-shot by the nearby GDR.
For me, I ended up going Religious Settlements as my pantheon to get the quick free settler, and I think that helped have a second city to get some more bombardments in. Having 2 cities, with Victor in, meant that I could actually kill a GDR once it got inside my territory. If I were to do it again, I would build less farms early on, to be able to handle them better. Given the disaster level, I do wonder whether trying to get a raging forest fire to get you your tile yields would have been better, but I was a little worried seeing those initial burnt woods not regrow that I wondered if they cheated and prevented all regrowth, and thus if your land burns it would become unworkable entirely. I'm curious whether Dance of the Aurora and trying to get a massive faith economy going to buy units with would have worked or not.