It’s funny, I had the exact same question. I’ve tried several games now, on the continents map, immortal. Most wonders I can get, but this one, it’s always gone by turn 100, even with only 5 other AIs competing.
Now I’m theorycrafting, trying to figure out how to build the damn thing in time. It’s not even that good for most builds, but if I’m doing something with border scaling (like celts + Epona), it seems important to get, so I’m sad when I keep failing!
I’m thinking that getting science going is critical. However, with Epona, border expansion helps science. So monument is still important on new cities, followed by council, then library (the instant these build, I lock the citizen into the scientist specialist slot, as keeping up with science on immortal is quite challenging).
I’ve also been going for great library, possibly followed by Teracotta Army. But I’m considering not bothering with Terracotta, as it increases the build cost of Angkor Wat. In fact… perhaps even the great library is a mistake due to the build costs. I will try skipping any other wonders and report back.