It's impossible to build quite a few things as Tenochtitlan (or any other mesoamerican nation) because there is not a sliver of tin on the market. I get that you're not supposed to make caravels and cross the Atlantic on your own (although that would be a neat, if weird, alternate history to try), but this also renders copper basically useless, despite there being a "copper works" tech for central americans, even stating that it would give us an advantage if we were to use it. Yeah, it probably would, if we could.
I think it would be better if we either were able to make tools (and possibly naval supplies, although I get why we can't) without a hard tin requirement, using either only copper or maybe a copper + gold mix?
That way, we'd be able to leverage the currently mostly useless copper mines, and copper tech available
(copper is apparently used for temple maintenance, but even without having built any mines myself, only AI built them, I still have a supply of 50 times the demand)
Either that, or have some small tin mines scattered through the Americas. Apparently, Aztecs had bronze by the 1300s, so they must've had a tin source
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