I mean most sweet and sour sauces are primarily a fruit, sugar, vinegar and a thickener... which pretty similar to ketchup. And those are considered okay to put on sushi.
For a lot of sushi, the chefs will be disappointed in you even for putting soy sauce on it. They craft it to have a specific combination of flavors, and strong sauces just obliterate them.
A regular tare sauce has sugar in it, and you can find the sweeter version (amadare) at sushi places. However, it's really only used for the eel (anago).
But I mean they make a ketchup spaghetti in Japan so if someone wants to talk about fucking with traditional dishes...
I mean, obviously you put whatever you want on yours no matter how much of a blatant crime against the universe it is, but "traditionally" that's not a thing. Takeaway shops do love their chili mayo though.