The soy doesn’t make the steak taste like Chinese food (not that there’s anything wrong with that) but rather just amps up the delicious. Oh, and this doesn’t have to be a tri tip - feel free to use any steak you want to be stupidly delicious.
If Grilling: heat grill to medium high, remove steak from marinade and cook, turning often (like every couple minutes) until a digital instant thermometer reads 130 for medium rare. Remove, cover lightly with foil and let rest 15 minutes before cutting against the grain to serve
If Roasting: heat oven to 275 degrees, put steak on a rack covered baking sheet, and cook until a digital instant thermometer reads 130 for medium rare. Because this was cooked at a low temperature, there’s no need to rest it. Remove, cutting against the grain to serve
BTW, you should serve this with the Sautéed Mushroom Caps