Quickly speaking, the Aztecs and Incas are Infantry civs with Siege Engineers. Mayans are an archer civ which earlier used Obsidian arrows to counter buildings along with Siege Rams. Obsidian arrows is gone. Also, Mayans lack Champions entirely, so they can’t even use Infantry to counter buildings. The only thing going for them is subpar Siege Rams.
They didn’t have obsidian arrows in AoC and they were still one of the top civs back then. They’ll be fine
Furthermore compared to AoC Mayan are still buffed against buildings thx to arson eagle warriors.
Siege Ram without Siege Engineers is stronger vs. buildings than Capped Rams with Siege Engineers, which is 200 vs. 180 damage. They’ll be fine.