Switch on Instant Pot. Turn on the Saute mode (press the Saute button).
Add sesame oil to the instant pot. Add chopped garlic to the oil and stir it for few seconds till it is fragrant (don't brown the garlic). Then add sliced onion and saute for a minute.
For the veggies, start with julienned carrots and saute for a minute. Now add broccoli florets and sliced capsicum and saute again for a minute.
Now add all the spices (salt, black pepper powder, minced garlic flakes, red chili flakes, mixed herbs and 21 salute seasoning) and give it a mix.
Now add all the sauces (Thai red curry paste, soy sauce, sriracha sauce and balsamic vinegar) and stir everything again. Press the Cancel button on Instant Pot.
Break the spaghetti into half and add to the instant pot. Now add coconut milk, water and unrefined cane sugar, and mix everything together. The wet ingredients (water and coconut milk should cover the veggies and spaghetti).
Sprinkle lemon grass and grated ginger on top. Close the lid. Press "Pressure Cook". If Pressure Level is seen as "Low", press the "Pressure Level" button (till you see "High" for pressure level). Set the pressure cook timer to 5 minutes. Turn the "Steam Release Valve" to "Sealing" position.
Once the instant pot beeps (after 5 minutes of pressure cooking), release the pressure manually immediately by turning the "Steam Release Valve" to "Venting" position carefully (make sure your hand is not right above the valve).
Open the lid once the pressure is released. Stir the noodles (spaghetti) and veggies thoroughly. Close the lid once again, without turning on the Instant Pot. After 2-3 minutes, open the lid and stir everything once again.
Thai red curry noodles are ready to be served. Garnish with toasted sesame seeds and chopped cilantro.