I would take over all the Americas. There is a lot of land and some nice rivers to spam cottages and tech like crazy. Get communism and assembly line then spam infantry out of 40+ cities to roll over everyone else with pure numbers. Add artillery and/or bombers if you get tired of brute forcing cities. You could also get tanks, but I think infantry should be fine to crush most of the map.
I think my early tech order is wrong for earth 18 always war as the Ai on continent are trading techs like crazy. I did only build 30 cities. I leave tech trading on.
My usual tech order Agg, mining (silver), TW, masonry, BW, Sailing, med, PH. (Oracle tech) Probably squeeze in fishing too. Usually try for mids for happiness and science. Sometime GLH. Could be doing too many wonders.
I wonder if missing colosus early on was a mistake with so many coastal cities. That would require copper to enable some nice fail gold. Copper involves a trek or a poorly placed city. Barbs are a real pain on this map with so much empty land.
So Early tech choices:
COL is nice for a religion. Speeds up CS. Caste is also good with spiritual. Would you really run caste when you need to whip?
MC for Colosus. Chance of fail gold too with copper. Copper takes a while to settle.
Maths offers bigger chops and HG. Is fail gold better than free pop on always war?
Alphabet offers science build and not much else on AW. Certainly think avoiding alphabet. Suggestion is just before PP. Can't trade techs anyway. Could steal but Gspy very unlikely.
Currency adds value if you have 2-3 island cities. Chance to run wealth to help speed up science.
Aesth line offers nothing economy wise. It's the economy stalling early on that is the biggest issue maybe?
Then a question of fail gold wonder economy vs rexxing fast vs caste specialist with mids. Bureau capital makes good sense. With 30 cities I was just not teching fast enough. I built lots of early wonders but missed Maus, Great Lib and music artist as too busy rexxing.
I normally move capital to west of where Washington is as it has so much cottageable land and can easily reach size 18 with double corn.
Ideally I need a huge fleet and stack of cuirs or rifles by about 1100ad or before. Getting the tech vs expansion is the big ask here. Or building so many cities I can reaqch 2-3k science a turn. Could of abused fail goild on Moai too.
If it was just about controlling the Americas it woud be easy albeit Ai do send fleets.