I'm trying to retarget your animations in godot to a character rigged with rigify. I created bone maps for both, but whatever I do the arms are always rotated incorrectly.

I recommend you use Rigodotify (a modified rigify more compatible with Godot) instead, that should fix any issues. https://felesmachina.itch.io/rigodotify
You can send me a message on Discord if you are still having trouble!