My wife has been trying to make green curry for years, but it was never as good as the Thai stuff. Then she followed the advice of a professional chef to not replace the kaffir limes by just any limes and actually try to obtain kaffir limes (which are bitter and not useful except for their peel). Boom! Her green curry is now as good as any in Thailand. Just changing the limes made a world of difference.
As for ketchup, it simply isn't spicy enough for my taste. Which makes it "boring". There's a Dutch variant called "curry" which contains spices and umami, but more sugar and less tomatoes.
Mayonnaise I desire with lemon, too (Belgian style). I like to make my own garlic sauce (Belgian mayonnaise, yogurt, cube-sliced garlic). Don't make it _too_ runny (too much yogurt). My fav sauce is green pepper sauce. It is similar to the garlic sauce as base, but with freshly grinded green pepper. I'll try a black pepper variant another time.
I also find that the older I become, the less desire I have for sugar. I dislike if things are too sweet for my taste. Hence I no longer prefer (Dutch) curry as sauce, and also a reason why I love yogurt with mayonnaise as a simple basis for sauces. In that sense, German cream and German mayonnaise is also lovely as it contains far less sugar but has the same mouth feeling. In apfelstrudel mit Sahne, the cream compliments the sweet pastry.
I'm not sure if there's cardamom in the curry, but it's definitely in the cupboard (both powdered and whole cardamom pods), so if it should be there, I expect it is.