RTF is a global modification that replaces all towns in the game.

Got it. Could you share a link to the file (geometry and texture, and ideally models and materials)? I'd like to take a look; maybe I can replace the "old" xuxo model with this new one...

.... xuxo's model is perfectly sized for the original Temple, but this one will stick out... it's better to find another one; thankfully, the developers in Anno included many buildings, so you can build your own city (and the game is all about that).

You could take a simpler church or an epic cathedral.